Abstract: Disclosed is a backpack having a gas mask. The backpack includes a body made of a sack shape and having a front surface and a rear surface, a pair of shoulder bearing straps attached to the front surface and at least one pocket positioned at the rear surface for receiving trifling articles, a mask overlapped over the front or rear surface of the body and having a detachable filter and an auxiliary cap for separately enclosing and sealing surroundings of a mouth and nose of a wearer, and an auxiliary cover installed to the rear surface of the body for opening/closing the mask. The backpack can be used as a gas mask to enable a wearer to evacuate from a dangerous area in case of emergency such as fire or toxic gas outflow.