Abstract: Mounting parts is performed by recognizing a particular part feeder where a part to be mounted is contained among a plurality of part feeders, moving a head unit to a position for picking up a part on the part feeder, moving an image sensor installed to be capable of moving to a position close to the particular part feeder, picking up a part from the particular part feeder with a suction nozzle installed at the head unit, moving the head unit to a position above the image sensor, detecting an image of the part held by the suction nozzle, moving the suction nozzle to a printed circuit board from the image sensor, and aligning the part with the printed circuit board while determining and compensating for an error generated when the part is picked up, and mounting the aligned part on the printed circuit board.