A scale base is fixed to a base in a plurality of locations which are aligned in a measuring direction (a Y direction) in which measurement by a scale is carried out, slits are provided in the scale base in positions lying between the locations where the scale base is fixed to the base, the scale is supported by the scale base in two or more of the locations where the scale base is fixed to the base, and the scale base has gaps between the base and the scale base in positions other than the locations where the scale base is fixed to the base and between the scale and the scale base in the positions other than the locations where the scale base is fixed to the base.