Provided is a field effect transistor including a graphene channel layer, and capable of increasing an on/off ratio of an operating current by using the graphene of the graphene channel layer. The field effect transistor includes: a substrate; the graphene channel layer which is disposed on a portion of the substrate and includes graphene; a first electrode disposed on a first region of the graphene channel layer and a portion of the substrate; an interlayer disposed on a second region of the graphene channel layer, which is apart from the first region, and a portion of the substrate; a second electrode disposed on the interlayer; a gate insulation layer disposed on a portion of the graphene channel layer, the first electrode, and the second electrode; and a gate electrode disposed on a portion of the gate insulation layer.