A double-tubular third transfer tube is provided in the transfer tube storage conduit, and a first transfer tube, second transfer tube and fourth transfer tube are installed in its interior. Further, pressure control valves are arranged in the portion of normal temperature, thereby reducing the amount of heat intrusion and the coolant temperature. This arrangement cryogenically cools down the irradiation coil and reception coil, without damaging the compressor, and ensures a low-temperature probe to be manufactured.