A stage device includes a stage configured to move in an X-axis direction and a Y-axis direction, an X-axis interference reflector spaced apart from the stage in the X-axis direction, a first X-axis interferometer disposed on the stage that is configured to measure an X-axis location of the stage using the X-axis interference reflector, and an optical movable element spaced apart from the stage in the Y-axis direction that is configured to shift in the X-axis direction a path of a light beam propagating in the Y-axis direction according to movement of the stage in the X-axis direction.