The picture retrieving apparatus includes: an orthogonal conversion coefficient memory 13 of a retrieval target picture storing an orthogonal conversion coefficient of a picture targeted for a retrieval; a picture feature amount converter 2 converting an orthogonal conversion coefficient 21 read from the orthogonal conversion coefficient memory 13 of the retrieval target picture into a color histogram information; and a color histogram similarity calculator 4 calculating a similarity 42 between a color histogram information 41 of a query picture and a color histogram information 25 generated by the picture feature amount converter 2. It unifies the kinds of the picture feature amounts to calculate the similarity between the picture feature amounts. Thus, it can specify the picture similar to the query picture from the retrieval target picture, on the basis of the calculated similarity.