A pressure sensitive copying paper comprising a sheet having on a support a coating layer containing finely divided cellulose powder (a) and mononucelus microcapsules (b) containing an oil solution of an electron donative colorless or light-colored dye, using an amino resin as film material and having a volume-average particle diameter of 5-10 microns (.mu.m) and a film thickness of 0.08-0.3 microns (.mu.m); and a sheet having on a support a coating layer containing an electron acceptant solid-state acid material which is reacted on contact with the dye to form a color. This pressure sensitive copying paper has the advantages such as excellent color forming performance, proofness against smudging, long-time storage stability, etc.