Robot hand, robot system, and method of positioning and gripping workpiece

The robot hand of the present invention comprises: a first abutting part which projects from a main body part in Z-direction, and has a first abutting surface against which a first surface of the workpiece abuts; second and third abutting parts which extend from the main body part, and against which the second and third surfaces of the workpiece abut respectively; and a suction member which is attached to the main body part so as to hold by suction the first surface. The suction member is deformable into an elongated shape where the suction surface is located in front of the first abutting surface in Z-direction, and into a contracted shape where the suction surface is located in back of the first abutting surface in Z-direction.