In order to eliminate a global phase change caused by static magnetic field inhomogeneity included in a nuclear magnetic resonance signal, focusing on that phase components generated in a nuclear magnetic resonance signal caused by the static magnetic field inhomogeneity is in a predetermined frequency band (low-frequency band), phase components in the frequency band caused by the static magnetic field inhomogeneity is eliminated from an image generated from the nuclear magnetic resonance signal in main imaging. The predetermined frequency band of the phase components caused by the static magnetic field inhomogeneity is calculated from the nuclear magnetic resonance signal obtained in preliminary imaging.
