a compact drilling system capable of improving working efficiency . the drilling system includes a drilling machine and a compressor . a control circuit controls performances of a drill motor in the drilling machine and an air compression motor in the compressor based on the detection result of a pressure sensor that detects a pressure within an air tank provided in the compressor . when one of the motors is activated , the other motor is not allowed to be operated and only when the drill motor is activated , compressed air is supplied from the air tank to the drilling machine . an electrical socket is provided in the compressor . a power cord extending from the drilling machine can be connected to the socket .