The present invention provides an evaluation aid which can be used as a phantom (imitation lesion) when a digital X-ray image thereof is taken and then evaluation is carried out through the digital X-ray image, and especially an evaluation aid which can be used for easily evaluating image qualities of a digital X-ray image for X-ray absorption parts having different X-ray absorption ratios at once. The evaluation aid of the present invention is adapted to be used for taking a digital X-ray image thereof through which evaluation is carried out, and contains a substrate (plate-like body) including a plurality of regions having different X-ray absorption ratios； and step members provided on the plate-like body so as to correspond to the plurality of regions, respectively, each step member including a plurality of subregions having different X-ray absorption ratios. It is preferred that thicknesses and/or constituent materials of the plurality of regions of the substrate are different from each other, so that these regions have the different X-ray absorption ratios.
