According to one embodiment, a semiconductor storage device includes a first stacked body, plate-shaped portions, and a wall portion. The first stacked body, in which electrically conductive layers and first insulating layers are stacked alternately one by one, includes pillar bodies that penetrate the electrically conductive layers in a stacking direction of the electrically conductive layers. The plate-shaped portions extend in a first direction intersecting the stacking direction and divide the first stacked body into blocks. The wall portion includes first and second portions. The first and second portions respectively extend in a second direction intersecting the first direction and the stacking direction and are arranged in the stacking direction. The second portion includes an outer edge connected to a side surface of the first portion and inclined with respect to the staking direction at an angle larger than an angle defined by the side surface and the stacking direction.