Abstract: An object of the present invention is to obtain information corresponding to information, which is readable by sight, but no longer visible. The present invention provides a chuck mechanism comprising: a chuck body including an installation surface and a side surface; and a master jaw provided on the installation surface of the chuck body and configured to move in a radial direction of the chuck body, wherein a first marking is provided on the installation surface of the chuck body, the first marking is product information of the chuck mechanism, the product information has a readable form by sight, and at least one second marking is provided on the installation surface or the side surface of the chuck body, the second marking is information including at least the product information of the first marking, and the information of the second marking has a coded form.

Abstract: An object of the present invention is to obtain information corresponding to information, which is readable by sight, but no longer visible. The present invention provides a chuck mechanism comprising: a chuck body including an installation surface and a side surface; and a master jaw provided on the installation surface of the chuck body and configured to move in a radial direction of the chuck body, wherein a first marking is provided on the installation surface of the chuck body, the first marking is product information of the chuck mechanism, the product information has a readable form by sight, and at least one second marking is provided on the installation surface or the side surface of the chuck body, the second marking is information including at least the product information of the first marking, and the information of the second marking has a coded form.

Abstract: The purpose of the present invention is to propose a magnet type medical instrument which can prevent the magnetic flux density from reducing remarkably even at a point distant from a magnetic pole of a core and realize a satisfactory pain-killing effect in a human body even at a point distant from the magnetic pole. The electromagnet for the magnet type medical instrument comprises a first core 1 with first inner space and a first coil 3 which is wound round the first core 1 and which can generate a first magnetic field by applying an alternating current, a commutated current or a pulsating current to the first coil 3.