Superconducting magnet device and method for manufacturing the same

A superconducting magnet device includes a vacuum container having a tubular barrel portion; a magnet assembly including a superconducting coil, a refrigerant tank, and a radiation shield, the magnet assembly being housed in the vacuum container; a supporting block fixed to the barrel portion and protruding beyond the barrel portion to the inside of the vacuum container; and a connecting portion which connects the magnet assembly and the supporting block to each other such that the magnet assembly is spaced apart from the barrel portion within the vacuum container. The connecting portion has thermal conductivity lower than thermal conductivity of the supporting member. The supporting member receives weight of the magnet assembly via the connecting portion while protruding inwardly beyond at least an outer circumference surface of the radiation shield of the magnet assembly.