A split type magnet device configured for a high-sensitivity NMR apparatus and used for solution analysis generates a uniform magnetic field at the center portion of the magnet device of at least 11 T, which is used for determining a sample. The NMR magnet device has left and right solenoid superconducting magnets, which face each other with a predetermined distance being provided therebetween. The left solenoid superconducting magnets and the right solenoid superconducting magnets are substantially coaxial to a central axis, and constituted respectively by a plurality of outermost magnets and a separate plurality of innermost magnets. When a sample energizing current generates a main magnetic NMR detection field in the vicinity of a center portion of the apparatus the current direction in at least one of the plurality of innermost magnets is minus while the current direction in at least one of the plurality of outermost magnets is plus.