1. An inspection apparatus comprising: a substrate surface detection unit configured to perform image analysis of cross-sectional images of an object to be inspected including a substrate and an electronic component and to specify, from the cross-sectional images, a surface image on which the surface of the substrate is photographed; a pseudo cross-sectional image creation unit configured to specify, based on the surface image, a region of solder for joining the substrate and the electronic component, the solder being photographed on the cross-sectional images, and to create a pseudo cross-sectional image in which an imaged region is made to have a thickness in a pseudo manner by piling up the cross-sectional images on which the solder is photographed; and an inspection unit configured to estimate whether a joint state of the solder is good or bad by performing image analysis on the region of the solder photographed on the surface image and on the region of the solder photographed on the pseudo cross-sectional image.