A stage system and a control method therefor. In one aspect, the stage system includes a stage which is going to be positioned, a magnetic material member provided on the stage, electromagnets disposed at opposite sides of the magnetic material member, a detector for detecting an electrical current value of a coil, which is a component of the electromagnets, and a position detector for detecting a position of the stage. The center position of the magnetic material member between the electromagnets can be determined on the basis of a relation between the position of the stage and the electrical current value of the coil, as the magnetic material member is moved relative to the electromagnets.