A superconducting magnet device includes a superconducting coil, a radiation shield, a vacuum case, an electrode member, and a conductive member. The conductive member includes an oxidized lead disposed in the radiation shield. The vacuum case includes a case body having an outer opening and an outer lid that is detachably attachable to the case body. The radiation shield includes a shield body having an inner opening and an inner lid that is detachably attachable to the shield body. The inner opening is formed in the region of the shield body that overlaps a portion of the outer opening when viewed in the direction from the outer opening to the oxidized lead.