A scanning exposure apparatus for exposing a substrate (8) to a pattern with an original (1) through a projection optical system (5), while scanning the original and the substrate, includes a first detection system (14c) which detects a first substrate reference mark (18c1, 18c3) corresponding to the substrate through the projection optical system on/at at least one of an optical axis of the projection optical and an off-axis position shifted from the optical axis in a scanning direction, and an alignment system (2, 9) which aligns the original and the substrate on the basis of a detection result of the first detection system.