A semiconductor memory device, including a first semiconductor pattern, and a second semiconductor pattern separated from the first semiconductor pattern in a vertical direction; a first bit line electrically connected to a first source/drain region of the first semiconductor pattern, and a second bit line electrically connected to a first source/drain region of the second semiconductor pattern; a word line structure in contact with the first semiconductor pattern and the second semiconductor pattern; and a first data storage element electrically connected to a second source/drain region of the first semiconductor pattern, and a second data storage element electrically connected to a second source/drain region of the second semiconductor pattern, wherein the first semiconductor pattern and the second semiconductor pattern are monocrystalline, and wherein a crystal orientation of the first semiconductor pattern is different from a crystal orientation of the second semiconductor pattern.