A switching device includes: a first layer including a carbon material having a six-member ring network structure; a first electrode electrically connected to a first portion of the first layer; a second electrode electrically connected to a second portion of the first layer and provided apart from the first electrode; a third electrode including a fourth portion provided opposing a third portion between the first portion and the second portion of the first layer; and a second layer provided between the third portion of the first layer and the fourth portion of the third electrode. The second layer includes: a base portion; and a functional group portion. The functional group portion is provided between the base portion and the first layer. The functional group portion is bonded to the base portion. A ratio of sp2-bonded carbon and sp3-bonded carbon of the first layer is changeable by a voltage applied between the first layer and the third electrode.