# What is Electronic Signature Act (Japan)?

> The Electronic Signature Act (電子署名法, Act No. 102 of 2000) is the Japanese law giving electronic signatures legal effect. Its Article 3 grants a presumption of authenticity to an electronic document signed by the principal using a signature only that person can perform — the provision that determines whether an electronic contract holds up in a Japanese court.

Last updated: 2026-08-07

- Japanese: 電子署名法 (でんししょめいほう / Denshi Shomei Hō)
- In English: Electronic Signature Act (also rendered: Act on Electronic Signatures and Certification Business)
- Governed by: Act No. 102 of 2000; jointly administered by MIC, METI and the Ministry of Justice.

Two service models are used in Japan, and the difference is who holds the signing certificate.

In the 当事者型 (principal-signature) model, each contracting party obtains its own certificate and signs with it. This maps most directly onto Article 3, but it requires every counterparty to complete identity verification and obtain a certificate — friction that stops many deals.

In the 立会人型 (service-provider-signature, also called 事業者署名型) model, the e-signature provider applies its own certificate at the instruction of the user, who is authenticated by email and other factors. This is the model most cloud e-contract services in Japan use, because the counterparty needs nothing but an email address.

The question of whether 立会人型 also attracts the Article 3 presumption was settled by joint government Q&A from the 総務省, 法務省 and 経済産業省 in 2020: it can, provided the uniqueness of the user's authentication process and of the provider's internal process are sufficiently assured. The 2020 cross-ministry material is published by the 総務省 (see sources). This is a summary, not legal advice — confirm the current text and consult counsel for your own contracts.

For procurement, the practical consequence is that 「電子契約に対応」 is not a single capability. Which model a tool uses changes what your counterparties must do, and that is often the deciding factor rather than price.

Sources: [1] https://www.soumu.go.jp/main_content/000711458.pdf [2] https://laws.e-gov.go.jp/law/412AC0000000102

## Related terms

- [Certified timestamp (認定タイムスタンプ)](https://agent-door.com/glossary/certified-timestamp)
- [Electronic Bookkeeping Act (電子帳簿保存法)](https://agent-door.com/glossary/denshi-chobo-hozon-ho)
- [Vendor evaluation](https://agent-door.com/glossary/vendor-evaluation)

## Frequently asked questions

### Is 立会人型 legally weaker than 当事者型?

Not categorically. The 2020 cross-ministry Q&A recognised that 立会人型 can attract the Article 3 presumption where the authentication and internal processes are sufficiently unique to the user. In practice the strength depends on how a given service implements identity verification, so it is a per-service question rather than a per-model one.

### Do all contracts in Japan allow electronic signature?

Most commercial contracts can be concluded electronically, but some categories have had statutory written-form or delivery requirements, and the rules have been amended repeatedly in recent years. Check the current requirement for your specific contract type with counsel rather than assuming blanket coverage.

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