For a purpose of improving homogeneity of an image obtained in a self-calibration by a parallel imaging method generally referred to as SENSE (SENSitivity Encoding), sensitivity factors S.sub.n(p) are calculated using an additive image A.sub.b=.SIGMA.|C.sub.n| of complex images C.sub.n obtained by conducting a calibration scan of an entire FOV for phased array coils Coil_n (n=1 N, N.gtoreq.2) (Steps V2, V3). Moreover, sensitivity maps S.sub.n are generated by conducting curve fitting by the method of least squares weighted by the square of a pixel value A.sub.b(p) of the absolute value additive image A.sub.b (Step V4).