A shutter base plate is made of synthetic resin and is configured with one overhang section on the blade-chamber-side surface at one end of an arcuate slot and the other overhang section on the blade-chamber-outside surface. A shock absorbing member made from elastic material is configured with concave portions on the blade-chamber-side surface and three concave portions on the blade-chamber-outside surface. The shock absorbing member is mounted to the shutter base plate in such a way that these concave portions come in contact with the overhang sections, and as is well known, when an exposure operation is completed, the driving pin of a driving member abuts on the shock absorbing member.