Abstract: A heat-sensitive mimeograph stencil which gives a high quality of image because the permeation of printing ink is not hindered by an adhesive, and which is free from the problems caused by an adhesive, that is, poor resistance to ink, sticking to thermal head, and generation of toxic chlorine, as well as production process thereof is disclosed. The heat-sensitive mimeograph stencil is prepared by thermally adhering a polyester film and a porous support consisting essentially of polyester fibers and then co-stretching the resultant, and the peeling strength between said polyester film and said porous support is not less than 1 g/cm, so that the printed matter obtained by mimeograph using the stencil has very high quality of image.