In the diffusion-weighted imaging, amounts of distortion and amounts of phase offset of k-space data due to a temporally changing magnetic field error induced by eddy currents and vibrations associated with application of a diffusion-weighted gradient magnetic field pulse are corrected with good precision to improve image quality. Characteristic data for correcting distortion of k-space data are calculated for every position in the slice direction as peak shifts of projections observed between the cases of applying and not applying an MPG pulse. As the characteristic data, amounts of distortion in the read-out direction and the phase encoding direction and phase offset amounts in a slice plane are calculated.