Provided is a graphene switching device including: a graphene layer formed on a substrate; a plurality of semiconductor nanowires on the substrate; a first electrode connected to a second end of the graphene layer; a second electrode on the substrate to face the first electrode so as to be connected to the plurality of semiconductor nanowires; a gate insulating layer on the substrate to cover the graphene layer; and a gate electrode on the gate insulating layer. The gate electrode and the plurality of semiconductor nanowires face each other with the graphene layer therebetween. At least one of the plurality of semiconductor nanowires is connected to at least one of the second electrode, the graphene layer, and the other of the plurality of semiconductor nanowires.