To prevent a shutter from being misopened without increasing the number of components.

A shutter blade 32 is composed of a blade part 42, a fitting hole 43, a projection 45 for preventing a projection for open from being misopened, and a pin 47. A shutter driving lever 55 has a kick lever 55a. When the shutter driving lever 55 rotates from its charge position to this release completion position, the kick lever 55a kicks a projection 44 for open away. When the shutter blade 32 is rotated by the kick lever 55a, the blade part 42 moves from the closure position where an exposure opening 41 is closed to the opening position where the exposure opening 41 is exposed. The shutter blade 32 which moves to the opening position is returned to the closure position by a spring 46 provided to the pin 47. At the charge position, the kick lever 55a is positioned between the projection 44 for open and the projection 45 for misopen prevention. Even if the shutter lever 32 rotates on receiving a shock, the projection 45 for misopen prevention is received by the kick lever 55a, so it never moves to the opening position.