Abstract: The present invention provides a novel polyamide acid resin (A) containing an unsaturated group, suitable to a photosensitive resin composition, and a photosensitive resin composition using the same, which is excellent in photosensitivity, and the resultant cured product is excellent in flexibility as well as adhesiveness, pencil hardness, solvent resistance, acid resistance, heat resistance, gold plating resistance, and the like. Said polyamide acid resin (A) containing an unsaturated group is obtained by reacting an unsaturated group-containing polyester resin (a) having a terminal anhydride group, and a compound (b) having two amino groups in a molecule, and said photosensitive resin composition is obtained by reacting a resin composition containing said polyamide acid resin (A) containing an unsaturated group, a crosslinker (B) and a photopolymerization initiator (C).