An oil pump device includes an oil pump (10) and an electrically operated control valve (20). The valve adjusts hydraulic pressures to be applied to a decrease-side control pressure chamber (15A) for causing a pump casing (14) to swing in the discharge amount decrease direction and an increase-side control pressure chamber (15B) for causing the pump casing to swing in the discharge amount increase direction so as to hold the pump casing at a predetermined approximately intermediate position between the maximum swing position in the discharge amount decrease direction and the maximum swing position in the discharge amount increase direction by balancing the urging forces of a decrease-side return spring (16) for urging the pump casing in the discharge amount decrease direction and an increase-side return spring (17) for urging the pump casing in the discharge amount increase direction when supply of current to the valve is stopped.