A resistive memory device includes a first word line extending in a first horizontal direction, a second word line extending on the first word line in the first horizontal direction, a third word line extending on the second word line in the first horizontal direction, a first bit line extending between the first and second word lines in a second horizontal direction, a second bit line extending between the second and third word lines in the second horizontal direction, and memory cells respectively arranged between the first word line and the first bit line, between the first bit line and the second word line, between the second word line and the second bit line, and between the second bit line and the third word line. A thickness of the second word line is greater than a thickness of each of the first word line and the third word line.