To eliminate failure that the conventional lens shutter single lens reflex camera using an existing lens requires very troublesome and confusing operation.

In the camera, an operation member on a camera body side is engaged with a shutter opening/closing member of the existing lens, and a mirror and a light-shielding plate, which are in a camera body, are motor-driven by the operation of the operation member, thereby activating two light-shielding means by one operation member, also a spring and a motor are used in combination for the operation of the mirror and the light-shielding plate, which are in the camera body.