To provide a resin composition that has excellent thickness accuracy, height uniformity, and gap-filling performance, and a semiconductor device with excellent flatness produced using the resin composition.

The resin composition including (A) a cyclic olefin polymer or a hydrogenated product thereof and (B) an oxetane compound, and the semiconductor device produced using the resin composition are provided. Preferably, the oxetane compound (B) has a structure represented by general formula (1).