There is provided a waterproof case which prevents ingress of water into the waterproof case through a protection piece, including a case body formed into a rectangular tube-like shape with a peripheral wall thereof and a lower cover having a bottom wall covering a lower opening of the case body and a peripheral wall extending from the bottom wall. The peripheral wall of the body case is placed so as to cover the peripheral wall of the lower cover. The protection piece is provided at the peripheral wall of the lower cover so as to sandwich the peripheral wall of the case body with the peripheral wall of the lower cover to prevent the deformation of the peripheral wall of the lower cover. There is also provided a protrusion protruding from a surface of the peripheral wall of the case body on which the protection piece is placed.