A camera system is composed of a lens unit and a camera body. The lens unit has a built-in CCD. A magnet is embedded in a protrusion of the lens unit. A case of the camera body is made of a magnetic material. In virtue of this, it is possible to attach the lens unit to any position of the camera body on condition that functions of the camera body are not disturbed by the lens unit. Incidentally, a cable is utilized to perform data transmission and electric-power transfer between the lens unit and the camera body.