A vacuum channel field effect transistor includes a first insulator on a p-type semiconductor substrate, a gate electrode on the first insulator, a second insulator on the gate electrode, a drain electrode on the second insulator, and an n+ impurity diffusion layer in the surface of the p-type semiconductor substrate, the n+ impurity diffusion layer being in contact with a side wall including side faces of the first insulator, the gate electrode, and the second insulator. Application of predetermined voltages to the n+ impurity diffusion layer, the gate electrode, and the drain electrode causes charge carriers in the n+ impurity diffusion layer to travel through a vacuum or air faced by the side wall to the drain electrode, which can increase the source-drain current.