A control valve for a variable displacement compressor for varying a discharging capacity of the compressor for compressing refrigerant led into a suction chamber and discharging the compressed refrigerant from a discharge chamber, by regulating a flow rate of the refrigerant led into a crankcase from the discharge chamber, the control valve comprising: a body having: a discharge chamber communication port that communicates with the discharge chamber; a crankcase communication port that communicates with the crankcase; a suction chamber communication port that communicates with the suction chamber; a main passage that communicates between the discharge chamber communication port and the crankcase communication port; and a sub-passage that communicates between the crankcase communication port and the suction chamber communication port; a main valve seat provided in the main passage; a main valve element configured to open and close a main valve by touching and leaving the main valve seat; a power element configured to supply a drive force in a valve opening direction to the main valve element according to a displacement amount of a pressure-sensing member, the power element including the pressure-sensing member for sensing a predetermined pressure-to-be-sensed and developing a displacement in an opening or closing direction of the main valve; a solenoid configured to generate a force opposing the drive force of the power element when the solenoid electrically conducts; an actuating rod configured to transmit a force generated by the solenoid to the power element, the actuating rod being coupled with the solenoid; a sub-valve seat provided in the sub-passage; a sub-valve element configured to open and close a sub-valve by touching and leaving the sub-valve seat; and a biasing member configured to bias the main valve element in a closing direction of the main valve, characterised in that a range of the pressures-to-be-sensed (Ps), where the main valve and the sub-valve are simultaneously closed until the sub-valve element is lifted from the sub-valve seat after the main valve element has been seated on the main valve seat, is set as a deadband, and a value of the pressure-to-be-sensed (Ps) with which to close the main valve, a value of the pressure-to-be-sensed (Ps) with which to open the sub-valve after the main valve has been closed, and pressure values at which the deadband takes place are set variably by setting a value of current supplied to the solenoid. a body having: a discharge chamber communication port that communicates with the discharge chamber; a crankcase communication port that communicates with the crankcase; a suction chamber communication port that communicates with the suction chamber; a main passage that communicates between the discharge chamber communication port and the crankcase communication port; and a sub-passage that communicates between the crankcase communication port and the suction chamber communication port; a discharge chamber communication port that communicates with the discharge chamber; a crankcase communication port that communicates with the crankcase; a suction chamber communication port that communicates with the suction chamber; a main passage that communicates between the discharge chamber communication port and the crankcase communication port; and a sub-passage that communicates between the crankcase communication port and the suction chamber communication port; a main valve seat provided in the main passage; a main valve element configured to open and close a main valve by touching and leaving the main valve seat; a power element configured to supply a drive force in a valve opening direction to the main valve element according to a displacement amount of a pressure-sensing member, the power element including the pressure-sensing member for sensing a predetermined pressure-to-be-sensed and developing a displacement in an opening or closing direction of the main valve; a solenoid configured to generate a force opposing the drive force of the power element when the solenoid electrically conducts; an actuating rod configured to transmit a force generated by the solenoid to the power element, the actuating rod being coupled with the solenoid; a sub-valve seat provided in the sub-passage; a sub-valve element configured to open and close a sub-valve by touching and leaving the sub-valve seat; and a biasing member configured to bias the main valve element in a closing direction of the main valve, characterised in that a range of the pressures-to-be-sensed (Ps), where the main valve and the sub-valve are simultaneously closed until the sub-valve element is lifted from the sub-valve seat after the main valve element has been seated on the main valve seat, is set as a deadband, and a value of the pressure-to-be-sensed (Ps) with which to close the main valve, a value of the pressure-to-be-sensed (Ps) with which to open the sub-valve after the main valve has been closed, and pressure values at which the deadband takes place are set variably by setting a value of current supplied to the solenoid.