To quickly inspect comprehensive photo-sensitizing characteristics of a photoreceptor relating to almost all issues affecting an image by utilizing an electrostatic image on the surface of the photoreceptor, without using toner like an image toner method.

With an electric-optical crystal 3 indicating such characteristics as a reflectance factor changes according to changes in electric field applied to a crystal utilized, a bottom surface 3a is made to approach the surface of a photoreceptor 2, which is to be inspected so that the electric-optical crystal 3 is assigned, and a polarization light is projected toward the surface of the photoreceptor 2, as to converge on the bottom surface 3a of the electric-optical crystal 3, thus, based on changes in polarization light of reflection light from the electric-optical crystal 3, defects of the photoreceptor are detected. Here, by utilizing the fact that changing condition in polarization direction is different based on the presence of defect on the photoreceptor 2 surface when the polarization light so projected as to converge on the bottom surface 3a is reflected, the presence of defect is judged based on changes in polarization in the reflection light.