A superconducting magnet apparatus which renders possible efficient, accurate and secure connection of a superconducting magnet current lead is provided. In the superconducting magnet apparatus of the present invention, a first current lead (21) and a second current lead (22) which compose a detachable current lead for excitation power supply are automatically attached to/detached from each other via a drive mechanism (30) using a piezoelectric ceramic. Therefore, professional skills in operation and maintenance required for this attachment/detachment operation are not necessary and the apparatus is easy to take care of. Also, no manpower is required even if a plurality of superconducting magnets are excited/demagnetized one after another, and efficient operation of the apparatus is possible. Furthermore, the piezoelectric ceramic is less subject to a magnetic field. Thus, the drive mechanism can be operated properly, and a contact pressure necessary for each attachment/detachment at a contact site between a lead contact portion (21a) and an attachment/detachment portion (22a) can be accurately obtained.