A stage apparatus includes a movable member configured to move in a direction parallel to a predetermined plane, a base member configured to support the movable member to move relative to the base member, and a thrust generator including: a magnet provided on one of the movable member and the base member, and a coil provided on the other of the movable member and the base member. The magnet and the coil generating a thrust to move the movable member in a direction parallel to the predetermined plane. A magnetic flux density of the magnet toward the coil changes along the thrust direction.