Before beginning a prior art imaging sequence, at first parts producing artifact are excited by applying a high frequency magnetic field thereto in a frequency band, which includes the parts emitting artifact and doesn't include a desired slice plane. Next, the phase of the excited spin is extremely rotated by applying at least one of gradient magnetic fields G.sub.x, G.sub.y, G.sub.z. When the prior art imaging sequence is effected thereafter, the produced artifact is imaged as a high spatial frequency component of an object body to be examined. Since a usual object body to be examined contains many low spatial frequency components and the power of high spatial frequency components is extremely small, it becomes possible to reduce the artifact in such an extent that it cannot be practically recognized.