A photosensitive resin composition of the present invention includes an
acid group-containing
vinyl ester resin and a photopolymerization initiator as essential components, wherein the
acid group-containing
vinyl ester resin is an
acid group-containing
vinyl ester resin having a multiple-branched molecular structure obtained by the following steps where a polybasic anhydride (a3) is reacted with an
epoxy vinyl ester resin (v1) that is a
reaction product of an aromatic
epoxy resin (a1) and a radically-polymerizable unsaturated-
double bond-containing monocarboxylic acid (a2); a radically-polymerizable unsaturated-
double bond-containing monoepoxy compound (a4) is subsequently reacted with an acid group formed by the reaction; and a polybasic anhydride (a3) is subsequently reacted with a secondary hydroxyl group formed by the reaction of the compound (a4) with the acid group, thereby obtaining the acid group-containing vinyl ester resin having a multiple-branched molecular structure; and contains 1.75 to 3.5 radically-polymerizable unsaturated double bonds per aromatic ring in the acid group-containing vinyl ester resin, and the acid groups within a range where the
acid value of the acid group-containing vinyl ester resin reaches 30 to 150 mg KOH / g. According to the present invention, a resin composition for a
resist ink that simultaneously has ultrahigh sensitivity, excellent developability, and broad
heat control range can be provided.