To provide a smaller-size and lower-cost electromagnetic expansion device having the function of a solenoid valve.

An orifice tube 15 is arranged in a passage in which a cooling medium flows and a valve element 16 is arranged contactable/separable with/ from the end face on the upstream side of the orifice tube 15. The valve element 16 is energized by a compression coil spring 20 arranged between a plunger 18 and a core 19 to make an orifice closed and the coil 23 is electrified to cause the attraction of the plunger 18 to the core 19 and the pull-off of the valve element 16 from the orifice tube 15 to make the orifice open. The smaller- size and low-cost device can be achieved by directly opening/closing a throttle by the orifice tube 15. The flow rate of the cooling medium corresponding to an air load is established by controlling the opening/closing of the throttle in accordance with a difference in temperature of the cooling medium at an access to a rear evaporator.