PURPOSE: To improve dark retentivity of surface potential, to enhance sensitivity and to form a good copied image by forming the first semiconductor film, an amorphous photoconductor film, and the second semiconductor film, and a film high in resistance on a substrate.

CONSTITUTION: The first semiconductor film 32 of P type a (amorphous)-Si, an undoped a-Si:H (amorphous Si hydride) film or an intrinsic a-Si:HB film (amorphous photoconductive film) 33, the second semiconductor film 34 of N type a-Si film, and a high-resistance a-Si film 35 are laminated in this order on a conductive substrate 31. For example, when positive DC corona charging is executed in the dark, positive electrostatic charge 36 is given on the film 35, and negative charge 37 is induced on the side of the substrate 31, but it is blocked with a potential barrier 38, the charge 36 is blocked with the potential barriers 39, 40 of the films 34, 35 to suppress the decay of the charge 36 to extremely low extents.