To provide a device for confirming the seating of a workpiece capable of confirming the seating of the workpiece by fixing the workpiece to one place without changing the mounting position when a plurality of the workpieces having different sizes of the outer diameter and various shapes are used in the device for confirming the seating which detects the proper mounting of the workpiece to a gripping device used for a machine tool.

The device for confirming the seating of a workpiece is provided with a receiving member, which is formed into a rod shape and downwardly presses a base by the seating of the workpiece, an energizing means for upwardly energizing the receiving member, and a fulcrum pin which axially supports one end of the receiving member and a body and connects the receiving member and the body rotatably. Even if the workpiece is seated anywhere in the receiving member, the base is pushed downwardly and the pressure of a fluid is let in/out. The seating of the workpiece is confirmed by the detection of the pressure of the fluid with a pressure detector.