The present invention addresses a challenge of providing a superconducting magnet device that enables it to realize an operation of opening and closing a permanent current switch of the superconducting magnet device at high speed with small electric heater capacity, avoiding an increase in the amount of heat incursion into the superconducting coil by not providing a driving mechanism from outside while enabling it to reduce refrigerant consumption or electric power consumed by a refrigerator, or an MRI apparatus using it having means for obtaining good image quality. The superconducting magnet device including a superconducting coil and a permanent current switch to enable it to realize permanent current flowing with the permanent current switch operated by an electric heater or an MRI apparatus using it has a heat transfer member to cool the permanent current switch from a cooling stage with solid conductivity and a thermal switch, and the thermal switch generates a gap in a heat transfer path including the heat transfer member for cooling and a refrigerator by thermal expansion when an electric heater is electrified.