A robot comprising: a first arm including a first hand tip and at least one joint shaft (A1, A2, A3), the first hand tip being provided at a tip end of the first arm, the at least one joint shaft (A1, A2, A3) being provided between a base and the first hand tip; a second arm including a second hand tip and at least one joint shaft (B1, B2, B3), the second hand tip being provided at a tip end of the second arm, the at least one joint shaft (B1, B2, B3) being provided between the base and the second hand tip; a controller configured to control the first arm and the second arm; a restricting member (7, 7A) configured to restrict a horizontal movement of a predetermined workpiece (WA, WB, WC, WD) in a state where the restricting member (7, 7A) is provided at the first hand tip; and a workpiece moving member configured to, in a state where the workpiece moving member is provided at the second hand tip, contact the workpiece (WA, WB, WC, WD) to horizontally move the workpiece (WA, WB, WC, WD) on a worktable by a horizontal movement of the second arm, wherein in order to perform positioning work of the workpiece (WA, WB, WC, WD) on the worktable, the controller is configured to perform a control operation of positioning the workpiece (WA, WB, WC, WD) at a stop position (Pw) on the worktable in such a manner that: based on predetermined size information of the workpiece (WA, WB, WC, WD) and preset stop position information regarding the stop position (Pw) on the worktable, the restricting member (7, 7A) is positioned at a predetermined restricting position on the worktable, the restricting position being included in the stop position (Pw) for the workpiece (WA, WB, WC, WD), and the workpiece moving member is brought into contact with the workpiece (WA, WB, WC, WD) and is moved toward the restricting position to horizontally move the workpiece (WA, WB, WC, WD) on the worktable; and the workpiece (WA, WB, WC, WD) is brought into contact with the restricting member (7, 7A). a first arm including a first hand tip and at least one joint shaft (A1, A2, A3), the first hand tip being provided at a tip end of the first arm, the at least one joint shaft (A1, A2, A3) being provided between a base and the first hand tip; a second arm including a second hand tip and at least one joint shaft (B1, B2, B3), the second hand tip being provided at a tip end of the second arm, the at least one joint shaft (B1, B2, B3) being provided between the base and the second hand tip; a controller configured to control the first arm and the second arm; a restricting member (7, 7A) configured to restrict a horizontal movement of a predetermined workpiece (WA, WB, WC, WD) in a state where the restricting member (7, 7A) is provided at the first hand tip; and a workpiece moving member configured to, in a state where the workpiece moving member is provided at the second hand tip, contact the workpiece (WA, WB, WC, WD) to horizontally move the workpiece (WA, WB, WC, WD) on a worktable by a horizontal movement of the second arm, wherein in order to perform positioning work of the workpiece (WA, WB, WC, WD) on the worktable, the controller is configured to perform a control operation of positioning the workpiece (WA, WB, WC, WD) at a stop position (Pw) on the worktable in such a manner that: based on predetermined size information of the workpiece (WA, WB, WC, WD) and preset stop position information regarding the stop position (Pw) on the worktable, the restricting member (7, 7A) is positioned at a predetermined restricting position on the worktable, the restricting position being included in the stop position (Pw) for the workpiece (WA, WB, WC, WD), and the workpiece moving member is brought into contact with the workpiece (WA, WB, WC, WD) and is moved toward the restricting position to horizontally move the workpiece (WA, WB, WC, WD) on the worktable; and the workpiece (WA, WB, WC, WD) is brought into contact with the restricting member (7, 7A).