PURPOSE: To operate a light emission part exactly, by detecting a brightness level of a field to be photographed, and displacing the light emission part to a prescribed position in case when the field to be photographed is darker than prescribed brightness.

CONSTITUTION: On a responding circuit D, a 3-stage coupling circuit 30 is provided by a pnp transistor, and an output signal of a comparator 26 is supplied to this coupling circuit 30 through a shutter-button switch 31. As a result, when an on-output signal of L voltage of the comparator 26, which is generated in case when a field to be photographed is darker than a prescribed level has been inputted, the coupling circuit 30 conducts and an electric power source is supplied to an electromagnetic device 32. Also, a capacitor 33 provided on the responding circuit D is charged by a tertiary coil of an ocillation transformer 2 before the shutter-button switch 31 is closed, and becomes an electric power source of the electromagnetic device 32 when the coupling circuit 30 has conducted. The electromagnetic device 32 is provided with a permanent magnet and a forward energizing coil, and is constituted so that electromagnetic force of the permanent magnet is erased and the light emission part is projected when a reverse energizing coil is turned on.