In a variable displacement pump, a pressurizing cylinder is provided on an opposite side of the first fluid pressure chamber, holding the cam ring there between, and a piston inserted to the pressurizing cylinder collides with the cam ring. An oil chamber of the pressurizing cylinder is interposed in a pump discharge side passage, and wherein a pressure in an upstream side of the main throttle provided in the pump discharge side passage is introduced to the first fluid pressure chamber and the oil chamber of the pressurizing cylinder, and a pressure in a downstream side of the main throttle is introduced to the second fluid pressure chamber.