Provided is a waterproof structure to prevent water ingress through an air hole in a casing of a communication device. A waterproof structure for a communication device, the communication device including a casing that houses an electronic substrate and has an air hole, includes a plate member facing the casing and attached to the casing such that the plate member covers the air hole, and a sealing member interposed between the plate member and the casing to prevent ingress of water into the air hole through a gap between the plate member and the casing.