A semiconductor device includes a first stacked body comprising first conductive layers and first insulating layers interposed therebetween, a first columnar portion comprising a first semiconductor layer extending in the first stacked body in the first direction and a first memory layer between the first semiconductor layer and the first conductive layers, a second stacked body comprising second conductive layers and second insulating layers interposed therebetween, and a second columnar portion comprising a second semiconductor layer extending in the second stacked body in the first direction and a second memory layer between the second semiconductor layer and the second conductive layers. The first columnar portion has a first diameter, and the second columnar portion has a second diameter, and each of the plurality of first conductive layers has a first film thickness, and each of the plurality of second conductive layers has a second film thickness.