A camera system includes a lens unit and a camera body to which the lens unit is detachably attached. The lens unit has a photographing lens, an imaging device which receives light transmitted through the photographing lens, and a lens-side connecting terminal for electric connection. The camera body has a camera-side connecting terminal which is connectable to the lens-side connecting terminal, and a movable member which is movable between a first position that is close to the camera-side connecting terminal and a second position that is far from the camera-side connecting terminal. The camera-side connecting terminal is shut in the camera body when the movable member is in the first position, and the lens unit can be attached when the movable member is in the second position.