This image processing device comprises a feature extraction unit, an attribute selection unit, and a determination unit. The feature extraction unit extracts a feature value of a target object from a plurality of images in which the same target object is reflected. The attribute selection unit selects an object attribute of the target object included in at least two of the plurality of images. On the basis of the object attribute selected by the attribute selection unit, the determination unit determines to combine the feature values of the at least two images when there is a difference in the object attribute among the at least two images.