Abstract: A flexible, heat resistant printed circuit board which comprises a laminate of:(A) a thin-wall body having a thickness of from 3 .mu.m to less than 5 mm which is a cross-linked product of a mixture composed of (1) at least one of an ethylene-acrylic acid copolymer and an ethylene-methacrylic acid copolymer, and (2) a saponified product of an ethylene-vinyl acetate copolymer, wherein the mixing proportion of copolymer (1) in the mixture is from 20 to 80% by weight and the mixture is cross-linked such that after extraction of the cross-linked product with a boiled toluene for three hours the amount of residue having a size of 0.1 .mu.m or more is at least 80% by weight based on the weight of the cross-linked product, and(B) an electrically conductive metal layer having a thickness of from 100 .ANG. to 400 .mu.m.The boards have excellent heat resistance, electrical insulating properties, flexibility, chemical resistance, dimensional stability, etc.