Exposure apparatus and device fabrication method

An exposure apparatus comprising:

• a projection optical system configured to project a pattern of a reticle onto a substrate;
• and
• a position detection apparatus configured to detect at least one of a position of the reticle and a position of the substrate,
• said position detection apparatus including
• an optical system which includes an optical member whose position can be changed,
• a photoelectric conversion device configured to receive light from a mark to detect the position of the reticle and the position of the substrate via said optical system, and configured to output a detection signal, and
• a control unit configured to control the position of said optical member based on information on a first evaluation value representing a symmetry of a waveform of the detection signal at each of a plurality of positions of said optical member, and information on a second evaluation value representing a position shift of the mark detected upon changing a position of the mark in an optical axis direction of said optical system at each of the plurality of positions of said optical member,
• wherein said control unit includes the information on the first evaluation value in advance.