A lubricating oil supply device that supplies hydraulic oil used to actuate a vehicle's transmission. The supply device configured with a pump that generates a hydraulic pressure, and a line pressure generation valve that discharges a part of the hydraulic pressure from the pump as a discharge pressure to generate a line pressure for actuating the transmission. A signal pressure output valve that outputs a signal pressure for actuating the line pressure generation valve in accordance with at least a throttle operation amount or torque input to the transmission. Furthermore, a switching valve that is actuated by the signal pressure from the signal pressure output valve and that supplies lubricating oil input to an input port to the object to be lubricated from an output port with a flow rate of the lubricating oil changed.