Component mounter and component holder imaging method

A component mounter comprises a mounting head that holds a plurality of nozzles. Two imaging positions are provided for the circumferential orbit along which the nozzles of the mounting head are arranged. While the nozzles are rotated continuously about the rotation axis, an operation of imaging the nozzles located at the imaging positions is performed for each of the imaging positions. Therefore, in a period when the nozzles rotate by an angle not larger than a predetermined angle around the rotation axis formed by the interval between the two imaging positions adjacent to each other along the circumferential orbit, imaging of the nozzles can be completed by locating each of the nozzles at one of the two imaging positions. As a result, it becomes possible to image the plurality of nozzles of the mounting head efficiently.