As a shutter release button is pressed down, a front end portion of a sequence drive lever moves toward the rear side and, as a result, a mirror-up lever is caused to rotate to the right by the force applied from a mirror up spring. In this state, a mirror drive end presses a mirror drive pin upward to raise a main mirror. In addition, a shutter drive end comes in contact with a shutter drive boss at a switching lever to push the shutter drive boss upward, thereby pulling the shutter blades downward. During a reset operation, the front end portion moves to the front side causing the mirror-up lever to rotate to the left. The main mirror is thus lowered. Since the switching lever is caused to rotate to the right with the force applied from a switching lever reset spring, the shutter blades are pulled upward to shield an opening.