The surface and the corona-shielding grating mounting structure of the electric device in the predetermined image with the positional relationship of the photoconductive member is disclosed. A corona charger and a photoconductive member is mounted on the support base member. The support base member has a mounting opening has an inverted U-shape of the shield member having a shield grid grating is inserted. The first locking projection is projected from the inner wall surface of the mounting openings, each of the first locking projection has a facing surface facing the surface of the photoconductive member practically formed as a locking surface perpendicular to the inner wall surface. Second locking projections of the second locking projection projecting from the inner wall surface, and each of the mounting opening has a face facing the photoconductive member practically formed as a locking surface perpendicular to the inner wall surface. The first locking projection and the lock hole are formed in the first shielding grid member in a position corresponding to the second locking projection. Shielding grid member is fixed and inserted into the mounting aperture through the coupling of the locking hole and the locking projection.