JPH0252496B

PURPOSE:To shorten the recovery time to a thermal equilibrium state of magnetization by making the magnetization in a relaxation process follow up an effective magnetic field by the effective magnetic field which is converted from the direction to which the magnetization is oriented, to the Z direction, after a nuclear magnetic resonance signal is observed. CONSTITUTION:A gradient magnetic field use coil is driven through a gradient magnetic field controlling circuit 8 from a controller 17, and a z gradient magnetic field is applied. At the same time, an exciting coil 4 is driven. In such a state, an observation is executed. After a nuclear magnetic resonance observation period is ended, it is stopped to apply all gradient magnetic fields Gz, Gx and Gy, and a resonance signal from a resonance frequency variable oscillator 9 is applied from the direction (y). In such a case, its frequency is lowered gradually from a resonance frequency of an object atomic nucleus, or form an appropriate frequency of a degree a little higher than its resonance frequency. As a result, an effective magnetic field converts its direction slowly in the direction Z, and the magnetization follows up this effective magnetic field and converts its direction in the direction Z.