Three-dimensional semiconductor memory device

According to one embodiment, a semiconductor memory device includes a substrate; an insulating layer provided on the substrate; a conductive layer provided on the insulating layer; a stacked body provided on the conductive layer and including a plurality of electrode layers and a plurality of insulating layers respectively provided among the plurality of electrode layers; a columnar section piercing through the stacked body to reach the conductive layer and extending in a first direction in which the stacked body is stacked; and a source layer. The columnar section includes a channel body and a charge storage film provided between the channel body and the respective electrode layers. The conductive layer includes a first film having electric conductivity and in contact with the lower end portion of the channel body; and an air gap provided to be covered by the first film.