To provide an easily openable envelope which is cut with scissors when opened, and easily openable without producing cutting waste.

The envelope 1 has its bending line 3 of a flap 2 deviated by 7 to 11 mm from a normal bending line 2b toward the end face of the flap 2. When the thus formed envelope is sealed, an opening 4 into which a paper knife 5 is insertable is formed at the side end of the normal bending line 2b, to thereby render the envelope easily openable and free from the production of waste.