There is provided is an optical member-holding apparatus which can hold a plurality of optical members of two different optical systems, even when the optical members exist in a common barrel in a mixed manner, such that the relative positions between the optical members can be easily adjusted; and which holds a mirror in a projection optical system and a mirror in an illumination optical system and includes a barrel unit, an inner ring holding the mirror, a holding member holding the mirror, a support plate attached to the barrel unit, and a holding-supporting mechanism attached to the support plate and adjusting the relative position of the mirror to the mirror.