PROBLEM TO BE SOLVED: To appropriately improve a contrast of a bone part of a subject in a radiation image.SOLUTION: A constituent image forming part 33 receives input of a plurality of radiation images which are formed of radiation transmitting through the subject and show a degree of transmission and attenuation in the subject of each of a plurality of patterns of radiation having different energy distributions and performs a weighted addition or subtraction on a corresponding pixel in the plurality of radiation images by using a given weight factor. Consequently, a body thickness information calculating part 34 acquires body thickness information representing a thickness of the subject in generating a bone part image showing the bone part in the subject, and a bone part emphasizing part 35 performs image processing on the bone part image in a manner to emphasize the bone part as the thickness of the subject becomes greater based on the body thickness information.COPYRIGHT: (C)2010,JPO&INPIT【課題】放射線画像中の被検体の骨部のコントラストを適切に向上させる。【解決手段】成分画像生成部33が、被写体を透過した放射線によって形成される、エネルギー分布の異なる複数のパターンの放射線の各々の被写体中の透過・減衰の程度を表す複数の放射線画像を入力とし、それら複数の放射線画像の相対応する画素毎に所与の重みづけ係数を用いた重み付き加減算を行うことによって、被写体中の骨部を表す骨部画像を生成する際に、体厚情報算出部34が、被検体の厚みを表す体厚情報を取得し、骨部強調部35が、その体厚情報に基づいて、被検体の厚みが大きいほど骨部が強調されるように骨部画像に対して画像処理を行う。【選択図】図3