A pump device for supplying a working fluid to a drive actuator for driving a drive subject through a control valve, comprising: a variable capacity first pump configured to supply the working fluid to the drive actuator, the first pump having a discharge capacity that varies in accordance with a tilt angle of a swash plate; a tilt actuator configured to control the tilt angle of the swash plate of the first pump in accordance with a control pressure supplied thereto; a regulator configured to regulate the control pressure by a control spool moving in accordance with a front-rear differential pressure on an upstream side and a pressure on a downstream side of the control valve; a fixed capacity second pump configured to be driven by an identical drive source to that of the first pump; a resistor provided in a pump passage through which the working fluid discharged from the second pump is led; a control actuator configured to operate in accordance with a front-rear differential pressure of the resistor so as to drive the regulator to reduce the control pressure in response to an increase in the front-rear differential pressure of the resistor; an auxiliary passage configured to lead an auxiliary pressure to the control actuator, the auxiliary pressure acting on the control actuator against either an upstream side pressure or a downstream side pressure of the resistor; and a switch valve configured to switch between a state in which the auxiliary pressure is supplied to the control actuator through the auxiliary passage and a state in which the auxiliary pressure is shut off; characterized by a controller configured to switch the switch valve to a state in which the auxiliary pressure is shut off and to switch a rotation speed of the drive source between a first rotation speed and a second rotation speed smaller than the first rotation speed, wherein the control actuator has a control piston configured to be moved until a differential-pressure driving force generated by receiving the front-rear differential pressure of the resistor and an auxiliary driving force generated by receiving the auxiliary pressure are balanced; and a pressure receiving area of the control piston on which the auxiliary pressure acts is set so that the auxiliary driving force corresponds to a change amount of the differential-pressure driving force accompanying switching of the rotation speed of the drive source between the first rotation speed and the second rotation speed. a variable capacity first pump configured to supply the working fluid to the drive actuator, the first pump having a discharge capacity that varies in accordance with a tilt angle of a swash plate; a tilt actuator configured to control the tilt angle of the swash plate of the first pump in accordance with a control pressure supplied thereto; a regulator configured to regulate the control pressure by a control spool moving in accordance with a front-rear differential pressure on an upstream side and a pressure on a downstream side of the control valve; a fixed capacity second pump configured to be driven by an identical drive source to that of the first pump; a resistor provided in a pump passage through which the working fluid discharged from the second pump is led; a control actuator configured to operate in accordance with a front-rear differential pressure of the resistor so as to drive the regulator to reduce the control pressure in response to an increase in the front-rear differential pressure of the resistor; an auxiliary passage configured to lead an auxiliary pressure to the control actuator, the auxiliary pressure acting on the control actuator against either an upstream side pressure or a downstream side pressure of the resistor; and a switch valve configured to switch between a state in which the auxiliary pressure is supplied to the control actuator through the auxiliary passage and a state in which the auxiliary pressure is shut off; characterized by a controller configured to switch the switch valve to a state in which the auxiliary pressure is shut off and to switch a rotation speed of the drive source between a first rotation speed and a second rotation speed smaller than the first rotation speed, wherein the control actuator has a control piston configured to be moved until a differential-pressure driving force generated by receiving the front-rear differential pressure of the resistor and an auxiliary driving force generated by receiving the auxiliary pressure are balanced; and a pressure receiving area of the control piston on which the auxiliary pressure acts is set so that the auxiliary driving force corresponds to a change amount of the differential-pressure driving force accompanying switching of the rotation speed of the drive source between the first rotation speed and the second rotation speed.