Provided is a synaptic device including a substrate, a channel layer on the substrate, a gate dielectric layer on the channel layer; and a gate electrode on the gate dielectric layer, wherein the gate dielectric layer includes a charge supply dielectric film and a piezoelectric film, wherein the charge supply dielectric film includes a metal oxide or metal sulfide, wherein the piezoelectric film includes a piezoelectric material that converts a pressure stimulation into an electrical signal, wherein accordance to a change in a signal applied to the gate electrode, a magnitude and aspect of a current flowing through the channel layer are changed.