A magnetic resonance signal is detected at a plurality of different periods of time in accordance with the phase shift of a plurality of chemical shift components while varying the intensity of a gradient magnetic field with time, a plurality of magnetic resonance signals thus obtained are used for estimating a magnetic resonance signal due to only a predetermined chemical shift component, the phase rotation of the predetermined chemical shift component is corrected in the estimated resonance signal, and further a blur due to chemical shift components other than the predetermined one is corrected to obtain a tomogram formed of only the predetermined chemical shift component. Alternatively, one measured resonance signal is modified by an image construction algorithm peculiar to each of a plurality of chemical shift components, to obtain tomograms corresponding to the chemical shift components.