To provide an envelope capable of preventing breakage of content such as cutting-off of the content when the envelope is opened without using a tongue-shaped stopper piece.

The envelope 1 is formed of a surface part and a back surface part 20 and has a content inlet 30 for putting in content C such as documents, and has a sealing piece 11 for sealing the content inlet 30 on the surface part. By folding the sealing piece 11 to cover the content inlet 30 and pasting to a pasting area 22 of the back surface part 20 across the content inlet, the content inlet 30 is sealed. On one or more points of the pasting area 22 of the back surface part 20, pasting avoiding windows 21 for avoiding pasting between the back surface part 20 and the sealing piece 11 are provided. On the pasting avoiding windows 21, the pasting by the sealing piece 11 is performed between an inner face of the surface part and the sealing piece 11 directly, not between the back surface part 20 and the sealing piece 11.