A variable displacement compressor control valve for varying a discharging capacity of the compressor for compressing a refrigerant led into a suction chamber and discharging the compressed refrigerant from a discharge chamber, said control valve regulating a flow rate of the refrigerant led into a control chamber from the discharge chamber, said control valve comprising: a body having a discharge chamber communication port communicating with the discharge chamber, a control chamber communication port communicating with the control chamber, a suction chamber communication port communicating with the suction chamber, and a valve hole provided in a passage connecting the discharge chamber communication port and the control chamber communication port; a valve element for opening and closing a valve section by touching and leaving a valve seat provided on an opening end of the valve hole; a solenoid, provided in the body, which generates a solenoidal force with which to drive the valve element in a valve closing direction according to an amount of current supplied to the solenoid; and a spring that applies a biasing force to the valve element in a valve opening direction, the biasing force opposing the solenoidal force, wherein the discharge chamber communication port, the control chamber communication port and the suction chamber communication port are formed in an order of the discharge chamber communication port, the control chamber communication port, and the suction chamber communication port starting from an end side of the body, and the solenoid is provided on another end side of the body, wherein the valve element autonomously operates so that a differential pressure (Pd - Ps) between a discharge pressure (Pd) of the discharge chamber and a suction pressure (Ps) of the suction chamber is kept at a preset differential pressure according to a value of current supplied to the solenoid, characterized in that the valve seat has a surface perpendicular to an axis line of the valve hole, the valve element is a flat valve having a flat surface that touches and leaves the valve seat and that is perpendicular to the axis line thereof, and the valve element comes in surface contact with the valve seat when the valve section is closed, wherein a seal section diameter (a) of the valve element at the valve hole is larger than a diameter (b) of a sliding portion of a transmitting rod (34, 68) in a guiding passage, and wherein when the valve section is opened from a valve closed state while the solenoid is energized, a force caused by a pressure in the control chamber acting on the valve element is larger in a valve closing direction than said pressure when the valve section is closed. a body having a discharge chamber communication port communicating with the discharge chamber, a control chamber communication port communicating with the control chamber, a suction chamber communication port communicating with the suction chamber, and a valve hole provided in a passage connecting the discharge chamber communication port and the control chamber communication port; a valve element for opening and closing a valve section by touching and leaving a valve seat provided on an opening end of the valve hole; a solenoid, provided in the body, which generates a solenoidal force with which to drive the valve element in a valve closing direction according to an amount of current supplied to the solenoid; and a spring that applies a biasing force to the valve element in a valve opening direction, the biasing force opposing the solenoidal force, wherein the discharge chamber communication port, the control chamber communication port and the suction chamber communication port are formed in an order of the discharge chamber communication port, the control chamber communication port, and the suction chamber communication port starting from an end side of the body, and the solenoid is provided on another end side of the body, wherein the valve element autonomously operates so that a differential pressure (Pd - Ps) between a discharge pressure (Pd) of the discharge chamber and a suction pressure (Ps) of the suction chamber is kept at a preset differential pressure according to a value of current supplied to the solenoid,