A semiconductor memory device includes: a bit line extending on a substrate in a vertical direction; a transistor body part including a first source-drain region, a monocrystalline channel layer, and a second source-drain region that are sequentially arranged in a first horizontal direction and connected to the bit line; gate electrode layers extending in a second horizontal direction that is orthogonal to the first horizontal direction, with a gate dielectric layer between the gate electrode layers and the monocrystalline channel layer, and covering upper and lower surfaces of the monocrystalline channel layer; and a cell capacitor including a lower electrode layer, a capacitor dielectric layer, and an upper electrode layer at a side of the transistor body that is opposite to the bit line in the first horizontal direction and is connected to the second source-drain region.