Abstract: An electrostatic photocopying apparatus has a charger adjacent to a photosensitive body, a retaining means for retaining and supplying image forming particles to the photosensitive body, a particle supply means for supplying the particles to the retaining means, and a single-layer producing means for applying to the image forming particles forces which are not sufficient to remove from the photosensitive body the image forming particles adhered directly to the photosensitive body, but are sufficient to remove the image forming particles attached in the second or higher layer thereover. The image forming particles can be evenly spread in one layer on the photosensitive body. Even if the photosensitive body is carried at high speed, the spreading operation can be carried out correspondingly. In addition, the starting and stopping of the spreading of the image forming particles can be easily performed and the amount of the image forming particles used can be reduced.