Abstract: A control device of a compressor includes a piston which reciprocates by a swash plate, a crankcase receiving the swash plate mounted such that an inclination angle thereof is variable, a discharge chamber from which a compressed working fluid is discharged, a suction chamber sucking the working fluid to be compressed, a first communication channel connecting the suction chamber and the crankcase, a second communication channel connecting the discharge chamber and the crankcase, and a control valve which selectively opens and closes the first communication channel and the second communication channel. The control device includes a suction pressure sensor measuring a pressure of the suction chamber, a valve control unit determining a target suction pressure on the basis of the value measured by the suction pressure sensor and a set temperature, and a valve driving unit controlling the opening degree of the control valve to achieve the target suction pressure.