By calculating the contour image representing the contour of the tissue on the magnetic susceptibility distribution, the estimation accuracy of the magnetic susceptibility value of the tissue is improved, and the background noise is reduced without lowering the magnetic susceptibility value of the tissue. An absolute value image and a phase image are calculated from the complex image obtained by MRI and a low frequency region magnetic susceptibility image having information of the magnetic susceptibility value of the tissue whose background noise is larger than a desired value is calculated from the phase image , A contour information susceptibility image having contour information of the structure of the magnetic susceptibility distribution although it is incorrect is calculated and a regularization parameter having the maximum contrast to noise ratio is used although the magnetic susceptibility value of the tissue is not correct Calculates the high frequency region magnetic susceptibility image calculated by the regularization method, calculates the contour mask from the contour information susceptibility image, smoothes the magic angle region from the contour mask and the low frequency region susceptibility image, finally calculates the high frequency region magnetic susceptibility Smooth the high frequency region using the image.磁化率分布上における組織の輪郭を表す輪郭画像を算出することにより組織の磁化率値の推定精度を向上させ、また組織の磁化率値を低下させずに背景ノイズを低減する。 MRIで得られる複素画像から絶対値画像と位相画像を算出し、位相画像から、背景ノイズは所望の値に比べて大きいが組織の磁化率値の情報を有する低周波領域磁化率画像を算出し、磁化率値は正しくないが磁化率分布の組織の輪郭情報を有する輪郭情報磁化率画像を算出し、組織の磁化率値は正しくないがコントラスト対ノイズ比が最大となる正則化パラメータを用いた正則化法で算出した高周波領域磁化率画像を算出し、輪郭情報磁化率画像から輪郭マスクを算出し、輪郭マスクと低周波領域磁化率画像からマジックアングル領域を平滑化し、最後に高周波領域磁化率画像を用いて高周波領域を平滑化する。