A digital still camera includes a camera body. A lens unit is retained on the camera body in a removable manner. A protection cover is secured to the camera body, and movable between a closed position and an open position, wherein the protection cover, when in the closed position, closes an exposure opening formed in the camera body, and when in the open position, opens the exposure opening. Cover moving transmission levers set the protection cover in the open position when the lens unit is retained on the camera body, and set the protection cover in the closed position when the lens unit is removed from the camera body. Furthermore, bayonet claw portions engage the lens unit with the camera body. The transmission levers are actuated in response to movement of the bayonet claw portions. A compression coil spring biases the protection cover toward the closed position.