1. A movement error detection apparatus of a mounting head to be applied to a component mounting apparatus equipped with a substrate conveyance device which includes a fixed conveyor extending in a first direction and a movable conveyor which is movable in a second direction orthogonal to the first direction with respect to the fixed conveyor, and equipped with a mounting head which mounts a component on a substrate conveyed by the substrate conveyance device to a predetermined work position, the movement error detection apparatus of a mounting head comprising:a movable region inside mark made of a projected image or a reflected image formed in a movable region of the movable conveyor;
a pair of movable region outside marks respectively provided on both sides of the movable region inside mark in the second direction and arranged outside the movable region of the movable conveyor and outward of the substrate at the work position;
an imager which moves together with the mounting head;
a controller which selects, among the movable region inside mark and the pair of movable region outside marks, two marks that are positioned on both outer sides of the substrate in the second direction and are closest to the substrate, and causes the imager to image the marks; and
a calculator which obtains a movement error of the mounting head on a basis of two mark images picked up by the imager.