A camera having a barrier according to the present invention includes a barrier unit in a space between a front main body and a front metal cover serving as an exterior member. Rotation of a barrier driving motor is transmitted to a rotary shaft member passing through the front main body, thereby allowing opening/closing actions of the lens barrier between a protection position for a photographing lens and a lens-barrier retracted position. The front main body is sealed waterproof by an O-ring provided to the outer circumferential surface of the rotary shaft member. With the lens barrel of the camera, rotation of a rotary moving frame is effectively transmitted to a cam frame through a cam follower fit to a linear-action groove, using a circumferential groove and the linear-action groove of a bayonet mechanism.