PURPOSE: To hold the first and the second electrifier in certain positions easily and surely with high precision to arrange them in positions of high electrification efficiency by supporting both electrifiers on a common frame.

CONSTITUTION: A cleaning device 54 and a prelamp 55 which removes electrification of outside peripheral faces of photosensitive drums 27 and 28 are provided in positions adjacent to outside peripheral faces of drums 27 and 28, and further, the first electrifier 56 which electrifies photosensitive drums 27 and 28 with the first polarity and the second electrifier 57 which electrifies them with the opposite polarity are provided successively. A pin 78 and a guide part 79 stood on the outside face of a frame 77 are fitted to a groove 75 and a notched part 76 of a supporting body 74 so that they are slid, and a recessed groove 81 with which a click ball 80 which is made elastic in the axial direction in the guide part 79 of the frame 77 is provided in the notched part 76. A lamp supporting leg 83 is attached to the frame by a screw 84, and rails 85, 85, 86, and 86 extending in directions of shafts 44 and 45 are supported by pairs of screws 87, 87, 88, and 88 so that their directions and positions are controlled, and slides 89 and 90 connected to the first and the second electrifiers 56 and 57 are fitted to these rails 85, 85, 86, and 86 so that they slide slides 89 and 90.