PURPOSE: To enable stable strobe tuned photographing to be accomplished by the simple constitution provided with a switching circuit which selectively changes over strobe photographing mode and auto photographing mode and a shutter speed setting circuit.

CONSTITUTION: At the time of performing strobe photographing in the state where a strobe circuit 11 and the electric circuit 12 of a focal plane electromagnetic shutter camera are held connected, turning ON of the power source switch SW201 of the strobe circuit 11 causes a capacitor C201 to be charged to operate a current detecting circuit CD, by which a capacitor C101 is shorted and when in this state a shutter release switch SW103 opens, the shutter is operated at the shutter speed corresponding to the time constants of the resistance R102 and capacitor C101, i.e., strobe tuning speed. When the auto photographing is set, the strobe power source switch SW201 is opened.