spring 36 the force of the spring 36 which upward pushes the stopper plate 26 via the valving element 32 is set to be greater than the pressure of the refrigerant in the operating chamber b which downward pushes the diaphragm 25 the diaphragm 25 is upward moved and thus the valving element 32 is also moved upward to open the valve in the valve open condition the liquid refrigerant which has flowed in the valve chamber 33 flows therefrom through the throttle 34 into the spring chamber 35 while adiabatically expanding and from the spring chamber 35 it flows out of the thermostatic subcooling control valve 10 through the outlet connecting portion 17 then it flows into the refrigerant evaporator 2 if degree of subcooling of the liquid refrigerant flowing into the inlet connecting portion 14 of the thermostatic subcooling control valve 10 becomes insufficient i e if temperature of the liquid refrigerant becomes high the refrigerant in the operating chamber b is expanded to increase its gas pressure in consequence the pressure which downward pushes the diaphragm 25 increases when the pressure becomes in excess of the total of the pressure of the influent liquid refrigerant in the operating chamber a which upward pushes the diaphragm 25 and the upward biasing force of the spring 36 the valving element 32 is downward moved the opening area of the throttle 34 is narrowed by the valving element 32 if the pressure in the operating chamber b is further increased the throttle 34 is eventually closed with the valving element 32 to stop the refrigerant from flowing into the refrigerant evaporator 2 as described above in the thermostatic subcooling control valve 10 of.