Proposed is a novel undercoating composition used in the photolithographic patterning of a photoresist layer by intervening between the substrate surface and the photoresist layer to decrease the adverse influences of the reflecting light from the substrate surface. The undercoating composition of the invention comprises (a) a melamine compound substituted by methylol groups and/or alkoxymethyl groups and (b) a polyhydroxy benzophenone compound, diphenyl sulfone compound or diphenyl sulfoxide compound, optionally, with admixture of (c) an alkali-insoluble resin of a (meth)acrylic acid ester.