The present invention addresses the problem of providing a semiconductor device having stable n-type semiconductor characteristics without deterioration over time. The purpose of the present invention is to provide a semiconductor device provided with: a substrate; a source electrode, a drain electrode and a gate electrode; a semiconductor layer which contacts the source electrode and the drain electrode; a gate insulation layer which insulates the semiconductor layer from the gate electrode; and a second insulation layer which contacts the semiconductor layer on a side opposite to the gate insulation layer with respect to the semiconductor layer, wherein the semiconductor device is characterized in that the semiconductor layer contains carbon nanotubes, the second insulation layer contains electron-donating compounds including at least any one selected from among nitrogen atoms and phosphorous atoms, and the oxygen permeability of the second insulation layer is equal to or less than 4.0 cc/(m²·24h·atm).