The cooling machine life by long, in order to reduce the rest period of the MRI apparatus for maintenance of the cooler, and the amount of heat entering the refrigerant vessel 202 of the superconducting magnet, so as to exert a cooling heat absorption to match almost, and to control the cooling capacity of the cooler 107 of the superconducting magnet, it is maintained within a pressure range which allows the pressure of the refrigerant vessel 202. At the same time, due to the pressure change in the refrigerant vessel 202, at least one of the variation of the magnetic field strength and uniformity of the magnetic field of the imaging space, it will be compensated by the magnetic field adjusting unit.冷却機の寿命を長くして、冷却機のメンテナンスのためのMRI装置の休止期間を少なくするために、超電導磁石の冷媒容器202へ侵入する熱量と、ほぼ一致する冷却吸熱を発揮するように、超電導磁石の冷却機107の冷却能力をコントロールし、冷媒容器202の圧力を許容する圧力範囲内に保持させる。それとともに、冷媒容器202内の圧力変化に伴う、撮像空間の磁場強度および磁場均一度の変化分の少なくとも一方を、磁場調整部により補償する。
