A photosensitive resin composition that excels in sensitivity to actinic energy rays (photosensitivity), is hardenable within a short period of time and can form pattern through development with a diluted aqueous alkali solution and that gives a cured film through thermal curing in the postcuring step, the cured film having satisfactory flexibility and being suitable to a solder mask ink of high insulation excelling in adherence and resistances of gold plating, electroless gold plating and tin plating; and a curing product thereof. In particular, a photosensitive resin composition characterized by comprising (1) a urethane resin (A) soluble in aqueous alkali solutions, the urethane resin obtained by urethanizing in the absence of catalyst a diisocyanate compound (a), a diol compound having an ethylenically unsaturated group in its molecule (b) and a diol compound having a carboxyl group in its molecule (c) optionally together with a diol compound not having any ethylenically unsaturated group or carboxyl group in its molecule (d) and reacting the reaction product with a cyclic acid anhydride (e); (2) photopolymerization initiator (B); and (3) a reactive crosslinking agent (C).