A controlling method for a nuclear magnetic resonance apparatus. The method includes: (A) cooling the high-temperature superconductor at a magnetization low temperature sufficiently lower than a superconductor transition temperature, and magnetizing the high-temperature superconductor with a magnetic field; (B) raising the temperature of the high-temperature superconductor at a magnetic flux setting temperature higher than the magnetization low temperature and lower than the superconductor transition temperature and setting a predetermined magnetic flux density; and (C) controlling the high-temperature superconductor in an operation temperature range lower than the magnetic flux setting temperature. Therefore, a strong static magnetic field comparable to a conventional superconducting magnet is formed without using a refrigerant (liquid helium) essential for operating the conventional superconducting magnet, and a magnetic flux density of the static magnetic field is held constant.