To provide an envelope with concealing paper which prevents stealing of personal information by that the envelope is sent to an address different from the original one due to alteration of the address of the envelope or to replacement of the envelope by some different one showing the different address.

The envelope 1 with the concealing paper comprises the envelope 5 having a constitution wherein envelope top paper 2 and envelope bottom paper 3 are stuck together at three peripheral sides and opened at one side, while a sealing piece 6 for sealing the side of the opening is provided on the side of the opening of the top paper 2. The address of the envelope 5 is expressed beforehand on the expression surface of the envelope top paper 2, while the concealing paper 10 concealing the address is stuck to the expression surface side of the top paper 2 by an adhesive 11 which enables peeling off, but is hard to restick after the peeling.