A flow controlling apparatus to control flow rate of working fluid discharged from pump apparatus to a power steering apparatus including a electric variable throttle, a solenoid mechanism and a spool. The solenoid mechanism varies opening degree of the electric variable throttle based on a electric signal from electric controller. The spool slides in accordance with the differential pressure of the variable throttle due to increase of flow rate of working fluid discharged from pump apparatus so as to return excess working fluid to bypass passage connecting to a suction port of pump apparatus. The flow controlling apparatus further comprising means for increase flow rate of bypass flow to bypass passage when rotating speed of the pump apparatus exceed predetermined value.