A voltage for light emission is applied to the positive electrode 11 and negative electrode 13 of a flash discharge tube 3 (xenon flash lamp) by a charge and discharge capacitor 17. When the voltage of the charge and discharge capacitor 17 does not reach a predetermined value, for example a voltage normally required for light emission operation of the flash discharge tube until a predetermined, for example, a time normally required to charge the charge and discharge capacitor 17, a timer circuit 39 generates a charging stop signal S3. A control circuit 35 controls to turn off the switch of a power supply 33 with reference to the signal S3 to stop the charging to the charge and discharge capacitor 17.