A semiconductor device includes: a stacked body with a plurality of conductive layers and a plurality of dielectric layers alternately stacked therein, the stacked body including a staircase structure having the plurality of conductive layers processed into a staircase shape; an interlayer dielectric layer covering the staircase structure; and a contact electrode provided inside a contact hole penetrating through the interlayer dielectric layer, the contact hole penetrating through one of the staircase-shaped conductive layers, the contact electrode being in contact with a sidewall portion of the one of the staircase-shaped conductive layers exposed into the contact hole.