Abstract: The process for producing a prepreg of a glass fiber cloth according to the present invention is characterized by heat-treating the inner portions of the selvages of the glass fiber cloth to remove the residual stress of glass fibers in the glass fiber cloth, coating the heat-treated portions of the glass fiber cloth with a solution of a saturated polyester type resin of 150.degree. to 180.degree. C. softening point insoluble in a thermosetting resin varnish to be later used for impregnation so that the amount coated becomes 4 to 10% by weight as resin based on the weight of the portions of glass fiber cloth coated, drying the resulging glass fiber cloth, removing the selvage portions of the glass fiber cloth by cutting, impregnating the selvages-removed glass fiber cloth with the above mentioned thermosetting resin varnish, and drying the impregnated glass fiber cloth.