Provided is a memory device comprising a molecular adsorption layer. The memory device includes: a substrate; a source electrode and a drain electrode formed on the substrate and separated from each other; a carbon nanotube (CNT) layer electrically connected to the source electrode and the drain electrode; a memory cell contacting the CNT so as to store a charge from the CNT; and a gate electrode formed on the memory cell, wherein the memory cell comprises: a first insulating layer formed on the CNT; a molecular adsorption layer which is formed on the first insulating layer and acts as a charge storage layer; and a second insulating layer formed on the molecular adsorption layer.