At least one exemplary embodiment is directed to a cam gear which can rotate counterclockwise to prepare for photographing. This rotation of the cam gear can cause a cam lever shaft to move from a first cam section that allows a shutter charging lever to be kept in a charged state, over a projection located near an end of the first section, to a second section configured to release the charged state. In conjunction with the movement of the cam lever shaft over the projection, the shutter charging lever momentarily moves from the charged position to an overcharged position, and then moves further to a pre-exposure retracted position.