A flash device for a lens-fitted photo film unit pre-loaded with unexposed
photo film is provided. A main capacitor stores charge. A flash emitter
emits flash light. A flash circuit board charges the main capacitor, and
drives the flash emitter by discharging the main capacitor in response to
an exposing operation. A tightly closed flash case is secured to the
lens-fitted photo film unit, for containing the main capacitor, the flash
emitter and the flash circuit board. Also, the lens-fitted photo film unit
includes a sync switch for generating a trigger signal in response to the
exposing operation. Two switch contact points are disposed outside the
flash case, for receiving the trigger signal from the sync switch. The two
switch contact points disable discharge of the main capacitor while the
flash case is away from the lens-fitted photo film unit, and are
short-circuited for discharge of the main capacitor upon supply of the
trigger signal while the flash case is secured to the lens-fitted photo
film unit.
