The present invention provides a stage apparatus including a first Y-axis interferometer which is supported by a base portion, and configured to detect a position of a first end surface of a table in a Y-axis direction, a second Y-axis interferometer which is supported by the base portion, and configured to detect a position of a second end surface of the table in the Y-axis direction, and a third Y-axis interferometer which is supported by the base portion so as to be spaced apart from the first Y-axis interferometer and the second Y-axis interferometer in an X-axis direction, and configured to detect a distance according to which a distance between the first Y-axis interferometer and the second Y-axis interferometer in the Y-axis direction can be obtained.