A drive member attached to the output shaft of a DC motor placed on a shutter base board includes a drive pin connected to the arm of a shutter blade within a blade chamber for driving the shutter blade to open and close an exposure opening with the reciprocal rotation of the DC motor. A brake member rotatably attached to the shutter base board and having a frictional force applied thereto by a spring washer brakes the rotation of the drive member when a bent portion is pushed by the drive pin to rotate.