The present invention provides an evaluation aid capable of using a digital X ray image as a phantom (mimic lesion) when the image is captured and evaluated and particularly evaluating digital X ray images in a plurality of X ray absorption regions having different X ray absorption rates in a collective manner. This evaluation aid is used when a digital X ray image is captured and evaluated and includes a substrate (plate like body) having a plurality of regions with different X ray absorption rates and steps having the plurality of regions with the different X ray absorption rates and provided correspondingly to the regions on the substrate. The substrate is preferably different in the X ray absorption rates in the regions because the thicknesses and/or constituent materials in the plurality of regions are different.
