A semiconductor memory device includes: a substrate; a memory cell array including memory cells arranged in a first direction intersecting a surface of the substrate; an insulating layer covering the memory cell array; and a transistor provided on the insulating layer. The transistor includes: first and second semiconductor layers provided on the insulating layer; a gate electrode provided between the first and second semiconductor layers, one end in the first direction of the gate electrode being closer to the substrate than the first and second semiconductor layers; a gate insulating film provided on the one end and on side surfaces of the gate electrode; and a third semiconductor layer facing the one end and the side surfaces of the gate electrode. The third semiconductor layer includes a crystal grain larger than a shortest distance between the insulating layer and the gate insulating film.