PURPOSE: To realize simultaneous photographing by using plural cameras whose time lag is variable.

CONSTITUTION: In a master machine, a release signal is transmitted to a slave machine, a first curtain 9 is started after the prescribed time lag and a signal for starting the traveling of the curtain is transmitted to the slave machine at the same time when a first release switch 1 is turned on. In the slave machine, the release signal from the master machine is received by a CPU 3 and exposure is prepared. Besides, when the traveling signal of the curtain is received, a first curtain control circuit 5 is immediately controlled and the curtain 9 is started. Then, the exposure is simultaneously executed by the master machine and the slave machine.