A variable resistance memory device includes memory cell stacks arranged in a first direction, the memory cell stacks including a first memory cell stack and a second memory cell stack. Each of the memory cell stacks includes a plurality of word lines, each word line of the plurality of word lines extending in a second direction intersecting the first direction and arranged in a third direction intersecting the first and second directions, and a memory cell connected to each of the plurality of word lines. Each of the memory cells includes a switching element and a variable resistance element. Each of the plurality of word lines of the first memory cell stack have a first thickness, in the first direction, of first word lines of the first memory cell stack is less than a second thickness, in the first direction, of each of the plurality of word lines of the second memory cell stack.