PURPOSE: To have a small-sized pumping device for car requiring low costs by equipping the pump's body with a means to sense low pressure which is proportional to the load of the pump and which does not require high pressure durability and thereby making it possible to sense simply and accurately the steering load etc.

CONSTITUTION: A pressure sensing means 23 in which the reduced pressure escaping from the discharge port 13 to low pressure port 15 of a flow control valve 10 is transmitted is led the pressure P3 between orifices 21A and 21B and the upper flow pressure P2 of the depressurizing orifice 21A into the inner 26A and outer 26B chambers of bellows 25 in the casing 27. The pressure sensing means 23 has a rod 28 which protrudes in compliance with the differential pressure between the pressure P2 and P3. Accordingly, sensing of this amount of elongation will give a measurement of the steering load, i.e. the load of the pump. Thus the steering load etc. can be sensed simply and accurately.