An electrostatic copying method of the transfer type which comprises repeatedly performing a copying cycle including an image-forming step of forming a latent electrostatic image on a photosensitive material moved through an endless moving path or a toner image obtained by developing it, a transfer step of transferring the latent electrostatic image or the toner image on the photosensitive material to a receptor member subsequent to the image-forming step, and a cleaning step of cleaning the photosensitive material subsequent to the transfer step. When the width or length of a receptor member to be used in the next copying cycle is found to be larger than the width or length of a receptor member used in the preceding copying cycle as a result of comparison of at least one of the width and length of the receptor member to be used in the next copying cycle respectively with at least one of the width and length of the receptor member used in the preceding copying cycle, the above cleaning step is additionally performed after the end of the preceding copying cycle before the next copying cycle is started.