PURPOSE: To reduce the driving power of a pump and as well eliminate the short supply of the pressurized fluid at the emergency handling of a steering wheel by a method wherein the supply of the pressurized fluid of the power steering arrangement is controlled in accordance with the load applied on the power steering arragement.

CONSTITUTION: The pressurized fluid delivered from a primary pump 1 is supplied through a pipe 2, a supply passage 4 formed in a casing 3, to the power steering arrangement 6 and flowed through a pipe 7 back to a tank 8. In the casing 3, both a flow regulating valve 10 and a change-over valve 25, which changes over the passage of a secondary pump 24 in accordance with the steering angle of the steering wheel 23, are provided. When the turning angle of the steering wheel is large, the valve 25 is moved rightwards by the action of a cam 31 and as a result the delivered oil from the pump 24 can be communicatively passed to the pipe 2 of the pump 1 through pipes 36, 34 and 39 and a check valve 41.