抄録
Maximum current of a superconducting magnet is restricted by maximum magnetic field. Therefore current density in low magnetic field regions becomes much smaller than critical current density in those magnetic field. This means that the superconductors are used inefficiently. A most simple way to use the superconductors more efficiently is to divid the magnet into several components according to their magnetic field strength.
A principle of deviding method to minimize the winding volume of the superconducting magnet is described on the basis some approximation.