A compressor controlling apparatus including a bypass unit connected between an outlet and an inlet of the compressor and a control unit. The control unit reduces pressure difference between the outlet and the inlet of the compressor by the bypass unit to start the compressor when the compressor is to be started. The compressor is started while pressure equilibrium is achieved by the bypass unit, thereby preventing poor start-up of the compressor caused due to excessive pressure difference, and thus improving reliability of the compressor.