A transistor includes: a substrate; a constant current formation layer provided on the substrate; a pair of source/drain patterns provided on the constant current formation layer; a gate electrode provided between the pair of source/drain patterns; a channel pattern extending in a direction between the pair of source/drain patterns; and a gate insulating layer surrounding the channel pattern, wherein the channel pattern penetrates the gate insulating layer and the gate electrode and is electrically connected to the source pattern and the drain pattern, the gate insulating layer separates the channel pattern and the gate electrode from each other, the constant current formation layer generates a constant current between the drain pattern and the substrate, and the constant current is independent from a gate voltage applied to the gate electrode.