PURPOSE: To obtain a titled power source device which is capable of controlling stably a spark discharge current of various modes, by providing a circuit for detecting a transient current variation quantity and current time width and for controlling the spark discharge by its logical output, on a pulse power source device.

CONSTITUTION: In a pulse power source for applying the pulsative high voltage to an electric dust collector, etc., a spark discharge current controlling circuit CON is connected to a pulse generating circuit PC. Spark discharge is detected by a time width detecting circuit DT2, and its detecting signal is inputted to one terminal of a logical circuit OR. Also, the variation quantity of transient current is detected by a detecting circuit DT1 and is inputted to the other terminal of the logical circuit OR. Outputs of these two kinds of discharge detecting signals are coupled and sent out to a control part 11. The control part 11 controls a thyristor-forced erasing circuit 6 by this signal, off-controls a switching thyristor 3 and turns off the spark generation.