Translation guide
A document that is meant to be kept secret or restricted to authorized persons. In Japanese, the most common and neutral term is 機密文書, but other expressions exist depending on context, such as internal company documents or classified government materials.
Please do not take this confidential document outside the company.
Literally 'secret document'. Slightly broader than 機密文書, can be used for any secret document, not necessarily official.
He was arrested on suspicion of leaking secret documents.
Top-secret document. Used for highly classified materials, often in government or military contexts.
The top-secret document is kept under strict security.
A document intended only for internal use within an organization, often marked as confidential.
A document whose access is restricted by law or regulation for national security reasons.
機密文書 is more formal and often implies official or organizational confidentiality, while 秘密文書 simply means a secret document and can be used in broader contexts, including personal secrets.
These terms are often used as stamps or labels on documents. They are not typically used in spoken language to refer to the document itself; instead, you might say 社外秘の書類 (company-confidential document).
部外秘の書類を他部署の人に見せてはいけません。
You must not show department-confidential documents to people from other departments.
Special procedures are required for managing designated confidential documents.