The purpose of the present invention is to provide a resin composition that exhibits a high storage stability in single-package form and that exhibits excellent properties and electrical characteristics for the cured product therefrom. Namely, provided are a resin composition comprising (A) a photobase generator comprising a compound represented by formula (1) (In formula (1), R1, R2, R3, R5, and R6 each independently represent, e.g., a hydrogen atom, hydroxyl group, alkoxy group, or organic group other than the preceding substituents. At least one of R4 represents an organic group that contains a thioether bond, and the other represents a hydrogen atom or an organic group that contains a thioether bond. The A represents a substituent represented by formula (1-1) or (1-2) (In formula (1-1), R7 and R8 each independently represent, e.g., a hydrogen atom, alkyl group, or heterocyclic group. In formula (1-2), R9 and R10 each independently represent an amino group or a substituted amino group.)), (B) an alkali-developable resin, and (C) a thermally reactive compound.