A cab includes a cab frame forming the cab, an outer roof configured to cover the cab frame from above and to be fastened to the cab frame from above, a seal mount protruding downwardly from an edge of the outer roof, and a seal material including a body portion having a recess for receiving the seal mount. The periphery of the body portion of the seal material has a seal lip for contacting the cab frame for sealing, and a drain groove for draining water entering between the seal material and the cab frame.