This invention relates to a stage device which is moved with high accuracy in an X-Y direction and a rotating direction using a planar motor. The invention is aimed at reducing the size of the stage device and at performing accurately measurement of a position of the stage to the base. The stage device comprises a scale unit having a scale part on the entire plane of the base, and three two-dimensional angle sensors disposed on a bottom surface of a movable stage part. The scale unit and the two-dimensional angle sensors form a surface encode. A position of the movable stage part is measured by the surface encoder.