A semiconductor memory device includes a silicon substrate including a first region which has a buried insulating layer below a single-crystal silicon layer and a second region which does not have the buried insulating layer below the single-crystal silicon layer, at least one memory cell transistor which has a first gate electrode, the first gate electrode being provided on the single-crystal silicon layer in the first region, and at least one selective gate transistor which has a second gate electrode and is provided on the single-crystal silicon layer in the first region. The one selective gate transistor is provided in such a manner that a part of the second gate electrode is placed on the single-crystal silicon layer in the second region.