A superconducting electromagnet is provided with a magnetic shield for protecting, from a leakage magnetic flux of the superconducting electromagnet, a motor for driving a cryocooler for cooling a cooling medium in a coil vessel, in which the superconducting coil is housed with the cooling medium. The magnetic shield includes a pair of ferromagnetic material plates placed opposite each other across the motor. Leakage magnetic fluxes in an opening space formed between a pair of the ferromagnetic material plates are attracted thereto to drastically reduce a density of the leakage magnetic fluxes around the motor. The opening space formed between the ferromagnetic material plates also facilitates maintenance of the cryocooler and the motor.