The rotating speed of the coating brush of the image forming apparatus fluctuates between the upper limit speed and the lower limit speed across the standard speed. Consequently, the positional relation of the contact between the brush textile of the coating brush and the surface of the photographic sensitive drum varies for a wider range compared to a case where the rotating speed of the coating brush does not vary. Since the thin area of the brush textile moves for a wider range of the surface of the photographic sensitive drum in the axial direction of the rotating shaft of the photographic sensitive drum, the area where the coating amount of the lubricant is less is evened out by the area where the coating amount of the lubricant is rich, thus improving the unevenness of coating of the lubricant on the photographic sensitive drum.