To improve printing durability even when a photosensitive layer is made thin without causing deterioration in the sensitivity and developing property by incorporating a quinone diazide compd. and a compd. having a specified structural unit.

This positive photosensitive compsn. contains a quinone diazide compd. and a compd. having the structural unit expressed by formula I or formula II. In formula I, R1 is a hydrogen atom or alkyl group having 1 to 6 carbon atoms, X is -CONH-, -CO2-, -O=, and Ar is an aryl group of 6 to 18 carbon atom. In formula II, R1, R2 are hydrogen atoms or alkyl groups having 1 to 6 carbon atoms and Ar is an aryl group having 6 to 18 carbon atoms. By this method, the obtd. positive photosensitive compsn. realizes improved printing durability without causing deterioration in sensitivity and developing property even when a photosensitive layer is made thin.