PROBLEM TO BE SOLVED: To enable similar case searches based on the distribution of lesions in diseases in which lesions are distributed in organs such as diffuse lung disease.SOLUTION: A computer executes a similar case image search program including the processing of: extracting an organ region from a medical image; dividing the organ region into a plurality of regions; counting the number of pixels indicating respective lesions of the divided regions; referring to a storage unit storing the number of pixels indicating the lesions for each region; and identifying similar case images corresponding to the degree of similarity of the number of pixels indicating the lesions.SELECTED DRAWING: Figure 1【課題】びまん性肺疾患などの臓器内に病変が分布する疾患における病変の分布に基づいて類似症例を検索できるようにする。【解決手段】類似症例画像検索プログラムであって、医用画像より臓器領域を抽出して、前記臓器領域を複数の領域に分割し、分割した前記領域のそれぞれの病変を示す画素の個数を計数し、領域ごとの病変を示す画素の個数を記憶した記憶部を参照して、病変を示す画素の個数の類似度に応じた類似症例画像を特定する、処理をコンピュータに実行させる。【選択図】図1