Notary Public (Koshonin) in Japan

The 公証人 (kōshōnin, "notary public") at your local 公証役場 (kōshō yakuba, "notary office") is Japan's authority for notarizing private documents: affidavits, certified copies, and the powerful 公正証書 (kōseishōsho, "notarial deed") that can make a contract directly enforceable.¹ Fees are fixed by cabinet order nationwide, and consultations about the work itself are free.²

Confirm current details with official sources

Procedures, fees, and requirements can change. Confirm current details with the Japan National Notaries Association or your local notary office. This article is general information, not legal advice; for divorce, debt, or inheritance matters, consult a licensed bengoshi.

Overview

A koshonin is a public official appointed by the Minister of Justice and attached to a Legal Affairs Bureau district.¹ Some 50 notary associations cover the country, with roughly 300 offices handling creation of notarial deeds, authentication of private documents and company articles, and attachment of certified dates.¹³ Government-issued papers are outside their lane entirely: official documents go to MOFA, never to the notary.³

What gets notarized

Notaries authenticate private documents only. Walk in with affidavits, contracts awaiting signature certification, company articles of incorporation, wills, or declarations, and the notary verifies identity, witnesses the signing or the acknowledgment of an existing signature, and applies the notarial seal.¹ A photocopy such as a passport page is handled through a declaration: you show the original, attach the copy to a signed statement, and the notary authenticates your declaration.³

Documents with illegal content, or papers with inserted, deleted, or altered text, can be refused or annotated at the notary's discretion.¹ Bring clean originals.

Check whether you need an oath or a plain certification

Some foreign offices demand an affidavit sworn as to truthfulness, not just a witnessed signature. Ask your recipient which one it wants, because the oath version costs more and cannot be downgraded afterward.³

Certification vs koseishosho

Simple certification evidences genuineness: the signature on the paper is really yours.¹ The koseishosho goes further. The office keeps the original deed and can issue an execution clause, which puts the creditor in the position of having already won a lawsuit: on default, compulsory execution can start without suing.³

That enforceability explains the standard uses: divorce agreements carrying child support, money-loan and lease guarantees, and business partnership agreements where payment certainty matters.¹ The 宣誓認証 (sensei ninshō, "oath certification") sits between: you swear the content is true before the notary and then sign, with sanctions backing a false statement.¹

Fees

Fees follow the cabinet Order on Notary Fees, so every office charges the same (figures below as of the current order text).⁴²

Service	Fee
Private-document certification	¥11,000 (or half the as-if-deed fee if lower)4
Foreign-language surcharge	+¥6,0004
Oath (affidavit) certification	¥11,000 flat (+¥6,000 if foreign-language)2
Transcript certification	¥5,0004
Certified date (確定日付, kakutei hizuke)	¥700 per item4
Koseishosho deed, value to ¥500k	¥3,0002
Koseishosho deed, value to ¥5m	¥13,0002
Koseishosho deed, value to ¥100m	¥49,0002

The table's fees carry their currency note here: confirm current figures with the notary office, since the order was revised by 2025 Cabinet Order No. 263.² Consultation about notarial work costs nothing, fees exclude consumption tax, and payment is cash or single-charge credit when the original is delivered.²

The visit

Book by phone before going. Some offices have a single notary who steps out for off-site work, and an appointment guarantees both presence and correctly prepared papers.¹³ Bring the document plus one photo ID from the accepted list: passport, driver's license, photo residence card, or My Number card; alternatively a seal certificate with the registered seal.¹ Company representatives add the company registration and the representative's seal certificate.¹

The procedure runs in Japanese. Private documents in any language can be notarized, but offices often need a Japanese translation of the paper, so prepare one in advance.³ If your Japanese is shaky, have a bilingual gyoseishoshi or bengoshi prepare the document and accompany you; this is the documented foreign-resident strategy, not an optional luxury for high-stakes deeds.³

Good to know

Public documents go to MOFA, never to the notary

Koseki, juminhyo, and other government papers skip the notary entirely and go straight to MOFA for apostille or authentication. Starting at the notary with one wastes a trip.³⁵

Foreign-language papers cost extra and may need a Japanese version

The ¥6,000 foreign-language surcharge applies per certification, and many offices ask for a Japanese translation alongside. Budget both before booking.⁴³

Book ahead; solo notaries step out of the office

A single-notary office closes whenever its notary leaves the building. A morning phone call secures the slot and confirms you carry the right ID.¹

See also

• The Four Divorce Paths
• The Kyogi-Divorce Form and Its Limits
• Koseki: Japan's Family Register Explained
• Apostille and Hague Convention Authentication

References

Footnotes

1. Japan National Notaries Association (JNNA). English guide (notary appointed by Justice Minister; private-document authentication; affidavit; ID list; fees). https://koshonin.gr.jp/pdf/english2.pdf ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸ ↩⁹ ↩¹⁰ ↩¹¹ ↩¹²

2. JNNA. Fee Q&A (koseishosho value table; private-cert ¥11,000; oath ¥11,000; consultation free; no consumption tax). https://www.koshonin.gr.jp/notary/ow12 ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸

3. Shibuya Notary Office. English pages (foreign-language handling; declaration route; official docs excluded; appointment advice). https://koshonin.com/english/ ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸ ↩⁹ ↩¹⁰

4. Order on Notary Fees (Cabinet Order; e.g. Art. 34 certification ¥11,000; foreign-language +¥6,000; transcript ¥5,000; date-certainty ¥700). https://www.japaneselawtranslation.go.jp/en/laws/view/4375/en ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶

5. Ministry of Foreign Affairs of Japan. Guide 1: Certifiable Documents (notarized private docs + Legal Affairs Bureau seal certificate → MOFA). https://www.mofa.go.jp/ca/cs/page22e_000418.html ↩