A compressor mounting device can be used for mounting a compressor to a vehicle body frame. The compressor mounting device includes a main body to be mounted to the vehicle body frame through first and second frame mounting units integrally formed to one end and the other end and including first and second compressor mounting units formed to be protruded upwardly between the first and second frame mounting units so as to be mounted to first and second lugs formed in the compressor. A main bush unit is mounted to the first and second compressor mounting units and connects the compressor and the first and second compressor mounting units through the first and second lugs to lessen vibration generated from the compressor from being transmitted to the vehicle body frame through the main body.