To provide a resin composition having high sensitivity to light and excelling in patterning property, especially a resin composition suitably usable for formation of a spacer provided joined to the functional surface side of a semiconductor element to determine a gap to be formed on the functional surface side of the semiconductor element or for formation of a protective film, an insulating film, or the like of the semiconductor element.

The resin composition contains a norbornene-based polymer having an epoxy group, and a photosensitizer which is onium salt of specific structure. The norbornene-based polymer is preferably an addition polymer. The content of the photosensitizer is preferably 0.1-10 pts.wt. based on 100 pts.wt. of the norbornene-based polymer. Preferably, the resin composition further contains an acid scavenger.