The flow control valve used in a variable displacement refrigerant compressor, which is incorporated in a refrigerating system, and arranged in a controlling passage fluidly interconnecting between a crank chamber and a discharge chamber or a suction chamber to regulate an opening formed in a predetermined portion of the controlling passage in a control characteristics in which when the discharge pressure of the refrigerant discharged from a discharge chamber of the compressor increases, the suction pressure of the refrigerant entering from the refrigerating system into a suction chamber increases. The flow control valve has a pressure sensing member for sensing of one of the suction and the crank-chamber pressure, and a valve element movable to increase and reduce the opening of the predetermined portion of the controlling passage on the basis of sensing of one of the suction and crank-chamber pressures by the pressure-sensing member.