A semiconductor memory device, and a method of manufacturing the same, includes: a gate stack structure including interlayer insulating layers and conductive patterns stacked in a first direction; a channel structure penetrating the gate stack structure; a peripheral contact plug spaced apart from the gate stack structure on a plane intersecting the channel structure, the peripheral contact plug extending in the first direction; and a capacitor spaced apart from the gate stack structure and the peripheral contact plug on the plane, the capacitor having an area wider than an area of the peripheral contact plug.