Abstract: A reactive power processing circuit for a current source GTO invertor in which a reactive current generated from a load of the GTO invertor is rectified by means of a fly wheel circuit and is sent to a capacitor so as to store a commutation surge voltage generated whenever a commutation of the invertor occurs, an excessive charge voltage across the capacitor is regenerated to a direct current output side of a power rectifier, and a pair of GTO (Gate Turn Off Thyristors) thyristors are connected between the capacitor and the direct current output side of the power rectifier in their forward directions so as to carry out a discharge operation for the excessive charge voltage across the capacitor. Consequently, with the number of circuit elements remarkably reduced, the reactive power processing at times of a high-frequency operation and acceleration/deceleration (variable speed) operation of the invertor can be achieved.