To provide a technique able to adopt a form for further improving the confidentiality for the content even in use of an envelope and reliably encourage the use of the envelope.
The self-addressed envelope 10 integrated with a concealment sheet includes: an envelope body 11 in which an enclosure such as an application form is enclosed; a flap 12 formed so as to be continuous with the envelope body 11, and used to seal the envelope body 11 with the enclosure enclosed therein; and a concealment 13 or the like integrated with the flap 12 in advance, required to be separated from the flap 12 when the envelope body 11 is sealed, and thereby enclosed in the envelope 11 together with the enclosure, with information written on the enclosure concealed. To send it back, the envelope body 11 and concealment 13 are cut off using perforations M, the enclosure is sandwiched by the concealment 13 cut off, and the sandwiched enclosure is enclosed in the envelope body 11. The envelope body 11 is sealed with the flap 12 and the envelope is sent back.
Kenji Tsuboi
Masao Tsuji