To highly precisely position a substrate without the loss of measuring time and stage moving time, and to precisely position the focal direction of a substrate against a projection optical system, by moving a stage and matching the average face of a photosensitive substrate with the pattern image-forming face of the projection optical system.

The main focal position of the projection optical system, namely, the height of the substrate at the center of a shot is measured. The position of the average face of the substrate is calculated by desirable measuring points based on them. The respective measuring points are weighted. An exposure position is moved, an automatic focus system 145 measuring the height of the substrate at the center of the shot detects the height of the exposure face, the substrate 202 is moved in the direction of Z with an inclination set angle is left as it is and exposure is started by driving a substrate stage 201. Then, they are repeated. At the time of the exposure of a liquid crystal panel, reticles 121-124 are exchanged and an exposure operation is repeated.