A robot includes: a restricting member configured to restrict a horizontal movement of a predetermined workpiece; and a workpiece moving member configured to generate an action for horizontally moving the workpiece. The controller performs a control operation of positioning the workpiece at a stop position in such a manner that: based on predetermined size information of the workpiece and preset stop position information of the workpiece, the restricting member is positioned at a predetermined restricting position included in the stop position for the workpiece, and the workpiece moving member acts on the workpiece and is moved toward the restricting position to horizontally move the workpiece; and the workpiece is brought into contact with the restricting member.