A public-bathhouse (sauna / sentō) business permit: the flow and required documents

To run a sauna, sentō or spa as a business you need a public-bathhouse permit under the Public Bathhouse Act (Article 2, paragraph 1). This article organises the difference between a general public bathhouse and 'other public bathhouses', the required drawings and documents, and how the public health centre, fire and building reviews run in parallel—and who to ask for each.

In short: to run a sauna, sentō or spa as a business you need a business permit under the Public Bathhouse Act. Anyone who intends to operate a public bathhouse as a business obtains a permit from the prefectural governor (in cities and special wards with a public health centre, the mayor or ward head) (Public Bathhouse Act, Article 2, paragraph 1). The permit may be refused where the location or the structural facilities are found unsuitable for public health, and so on (same Article, paragraph 2), and the concrete standards for structural facilities and hygiene measures are delegated to each prefecture's ordinance (Article 2, paragraph 3, and Article 3, paragraph 2). Conformity with the use zone and change of use (Building Standards Act) and the fire laws is also a prerequisite. This article organises the conditions and flow; eligibility is decided by the public health centre's review, and our office does not guarantee a permit.

What law is a sauna or sentō business permit based on?

To operate a public bathhouse as a business you need the prefectural governor's permit under the Public Bathhouse Act (Act No. 139 of 12 July 1948). Article 1 defines a "public bathhouse" as a facility that uses hot water, seawater bath, hot spring or the like to have the public bathe. A sentō, a sauna (one with a cold-plunge or other tub), and a super-sentō are all public bathhouses if they fall within this definition.

The permitting authority is the prefectural governor. However, in cities with a public health centre (designated cities, core cities, etc.) and in special wards, the mayor or ward head is the authority (Public Bathhouse Act, Article 2, paragraph 1). The authority may refuse the permit where it finds the location or the structural facilities unsuitable for public health, or the location lacking proper placement (same Article, paragraph 2). Because the standards for structural facilities (ventilation, lighting, illumination, heat retention, cleanliness and other measures needed for bathers' hygiene and decency) are delegated to prefectural ordinance (Article 3, paragraphs 1 and 2), confirm the figures and layout with the ordinance of the opening area and the public health centre's guide.

Whether some sauna facilities that use only steam or hot air and have no tub (including a cold-plunge) require a permit under the Public Bathhouse Act can be judged differently by municipality depending on the facility's form. On this point, consulting the public health centre of the opening area just before writing is the sure route. Because we have not been able to confirm it, here we limit ourselves to the general treatment that "a sauna, sentō or spa with a tub is a public bathhouse."

How does the permit differ between a general public bathhouse and "other public bathhouses"?

In practice, public bathhouses are handled in two categories: "general public bathhouses" and "other public bathhouses". The former are so-called sentō; as facilities necessary for daily local life, their bathing fees are controlled by the governor (under the Price Control Order, Imperial Ordinance No. 118 of 1946). The latter are types such as saunas, super-sentō, health-land and private-room bathhouses, which can set fees freely.

	General public bathhouse (sentō)	Other public bathhouse (sauna, etc.)
Governing law	Public Bathhouse Act, Article 2, paragraph 1	Public Bathhouse Act, Article 2, paragraph 1
Bathing fee	Controlled by the governor (Price Control Order)	Can be set freely
Placement standard (distance limit)	Subject to the ordinance's distance limit	In principle not subject
Structural facilities / hygiene	Conform to the ordinance's standards	Conform to the ordinance's standards

The big differences are the placement standard (distance limit) and fees. Public Bathhouse Act, Article 2, paragraph 3, delegates the placement standard for the location to prefectural ordinance. This distance limit targets general public bathhouses (sentō); "other public bathhouses" such as saunas are in principle not subject to it. However, the standards for structural facilities and hygiene measures must be met by both, and this is not waived for a sauna. Which type your facility is reviewed under depends on the operating form and the ordinance, so confirm with the public health centre.

What drawings and documents are required for the application?

The permit application requires, besides the application form, drawings of the facility and documents showing the equipment. Forms and copies vary by municipality, but typical ones are as follows.

Document	Outline
Business permit application	The operator, the facility's location, the type of business, etc.
Floor plan / layout of the facility	Positions and dimensions of the bathroom, changing room, toilets, washbasins
System diagram of water supply/drainage and circulation-filtration	Routes of hot-water supply, drainage, circulation-filtration, chlorine disinfection
Ventilation equipment drawing	Ventilation routes of the bathroom and changing room
Materials on the quality of the water used	Water-quality test results, etc., where well water is used
Certificate of registered matters, etc.	Documents showing standing where the operator is a company

Where a circulating tub is installed, measures against Legionella bacteria are the focus of the review. The Ministry of Health, Labour and Welfare's "Guidelines for Hygiene and Other Management in Public Bathhouses" (Seiei-hatsu No. 1811 of 15 December 2000; amended by Seishoku-hatsu No. 1210001 of 10 December 2020) sets out cleaning of the circulation-filtration device, removal of biofilm inside the piping, and appropriate-temperature management of the storage tank. Building the hygiene measures into the design from the equipment-design stage, in line with these guidelines and each prefecture's ordinance, is necessary.

How do the public health centre inspection and the fire and building checks run in parallel?

When opening a public bathhouse, three counters—the public health centre (permit), the fire station (fire laws), and building (use zone and change of use)—move separately. Operation cannot start with only one of them in place.

On the fire side, a public bathhouse (including a steam bath and a hot-air bath) is a fire-defence-target property listed in the Appended Table 1 of the Order for Enforcement of the Fire Service Act, and, depending on scale and capacity, the installation of fire-fighting equipment (automatic fire alarm, guidance lights, extinguishers, etc.) is required. In the building-confirmation and permit scenes, the consent of the fire chief or fire station head is involved (Fire Service Act, Article 7).

On the building side, a public bathhouse is a special building under the Building Standards Act (Article 2, item 2). When converting an existing building into a public bathhouse, if you carry out a change of use so that the total floor area of the part used for that purpose exceeds 200㎡, a confirmation application is required (Building Standards Act, Article 87, paragraph 1; the amendment easing the threshold from over 100㎡ to over 200㎡ took effect on 25 June 2019). As with hotels and inns, there are also location restrictions by use zone. Confirming, before signing the premises contract, the prospects for the use zone and change of use and the need for fire-fighting equipment is important to avoid rework. Closely related points are also organised in Hotel-business (simple-lodging) permit.

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Who should you ask for the permit application, building and premises?

Opening a public bathhouse crosses several fields of expertise. The roles are divided as follows.

Preparation of the public-bathhouse permit application and attached documents, and support for prior consultation with the public health centre → Yotsuba Administrative Scrivener Office (administrative scrivener)
Selection, lease and important-matters explanation of the business premises → Yotsuba Real Estate Co., Ltd.
Building use, confirmation application, change of use, and checking the certificate of inspection → an architect and the specified administrative agency
Design and works of fire-fighting equipment, fire consent and inspection → a fire-equipment engineer and the fire authority
Accounting and tax of the building and business → a tax accountant
Individual legal judgement on rights, obligations and disputes → an attorney

Yotsuba Administrative Scrivener Office and Yotsuba Real Estate Co., Ltd. are separate businesses. Our office handles only support for the public-bathhouse permit application as an independent business, and premises, building, fire and tax are contracted or consulted separately with each qualified professional and administrative counter. Our office receives no referral fee. For the whole picture of licensing, see Licensing and Permits; for the flow of engagement, see Engagement Flow; and for fees, see Fee Schedule. If you also run food service, see Restaurant business permit and the public health centre's facility standards; if lodging is involved, also check Housing accommodation business notification. Eligibility itself is decided by the public health centre.

FAQ

Q. Is a sauna the same permit as a sentō?
A. The basis is the same permit under Public Bathhouse Act, Article 2, paragraph 1, but the operational type differs. A sentō is a "general public bathhouse" whose bathing fees are controlled by the governor (Price Control Order) and which is subject to the ordinance's distance limit. A sauna, super-sentō and the like are "other public bathhouses": fees can be set freely and they are in principle not subject to the distance limit. However, both must meet the ordinance standards for structural facilities and hygiene measures.

Q. Does installing a circulating tub make the review stricter?
A. Measures against Legionella bacteria become the focus. The Ministry of Health, Labour and Welfare's "Guidelines for Hygiene and Other Management in Public Bathhouses" (Seiei-hatsu No. 1811 of 15 December 2000; amended 10 December 2020) sets out cleaning of the circulation-filtration device, removal of biofilm inside the piping, and management of the storage tank. Because equipment and operation in line with these guidelines and each prefecture's ordinance are required, build the hygiene measures in from the design stage.

Q. Can you convert a room in an office building into a sauna and operate?
A. A use-zone and change-of-use check is needed. A public bathhouse is a special building under the Building Standards Act, and a change of use where the part used for that purpose exceeds 200㎡ requires a confirmation application (Building Standards Act, Article 87, paragraph 1). There are also use-zone location restrictions. Because eligibility is judged by the specified administrative agency and an architect, confirm the prospects before signing the premises contract.

Q. How long does the permit take?
A. It cannot be said in general, because it varies with the facility's scale, the necessary works, and the state of coordination with the public health centre, fire and building counters. In many municipalities the flow is: prior consultation before construction → check of drawings, etc. → works → on-site inspection after completion → permit. Confirm the standard processing period and required documents on the official page of the opening area's public health centre.

Sources (Primary Information)

e-Gov Law Search, "Public Bathhouse Act" (Act No. 139 of 12 July 1948), Article 1, Article 2 paragraphs 1–3, Article 3 paragraphs 1 and 2 (accessed 2026-09-16)
e-Gov Law Search, "Building Standards Act" (Act No. 201 of 1950), Article 2 item 2 (special building), Article 87 paragraph 1 (change-of-use confirmation) (accessed 2026-09-16)
e-Gov Law Search, "Fire Service Act" (Act No. 186 of 1948), Article 7 (fire consent), and Appended Table 1 of the Order for Enforcement (fire-defence-target property) (accessed 2026-09-16)
Ministry of Health, Labour and Welfare, "On the Guidelines for Hygiene and Other Management in Public Bathhouses" (Seiei-hatsu No. 1811 of 15 December 2000; amended by Seishoku-hatsu No. 1210001 of 10 December 2020) (accessed 2026-09-16)
Control of the bathing fees of general public bathhouses under the Price Control Order (Imperial Ordinance No. 118 of 1946) (designation by each prefecture; accessed 2026-09-16)
Guides to public-bathhouse permit applications published by the public health centre of the planned site, and each prefecture's ordinance for enforcing the Public Bathhouse Act (standards for structural facilities, hygiene measures and placement; accessed 2026-09-16)

This article is general information and does not guarantee individual eligibility for a permit, the standards for structural facilities and hygiene measures, or conformity with the use zone, change of use or fire laws. The final review of the public-bathhouse permit is made by the public health centre (prefecture, city with a public health centre, or special ward). The concrete standards for structural facilities, hygiene measures and placement are delegated to each prefecture's ordinance; confirm the standards, forms and required documents for each facility on the relevant municipality's official page. Judgements on the use zone, change of use and existing non-conformity are made by the specified administrative agency and an architect, and the need for fire-fighting equipment by the fire authority and a fire-equipment engineer. Selection, lease and important-matters explanation of the business premises are handled by Yotsuba Real Estate Co., Ltd.; building confirmation and change of use by an architect and the specified administrative agency; design and works of fire-fighting equipment by a fire-equipment engineer and the fire authority; accounting and tax by a tax accountant; and individual legal judgement on rights, obligations and disputes by an attorney, each as an independent business under a separate contract or consultation. Our office receives no referral fee. Individual judgements are made by a qualified professional after a meeting. Written by Joji Uramatsu, administrative scrivener and licensed real estate broker.