The present invention relates to a deflecting device for deflecting a flux of passing light rays by causing an optical member to move in a plane perpendicular to or approximately perpendicular to the optical axis of an optical system, such as a photographic optical system, in parallel with the plane and making the optical axis of the movable optical member eccentric with respect to the optical axis of the optical system, or to an optical apparatus, such as an image-shake correcting device, for correcting an image shake by the deflection of a pencil of passing light rays. In such a device, there is provided an adjusting mechanism, such as an eccentric shaft or mechanism for supporting the optical members at a plurality of supporting points, for adjusting an inclination of the optical axis of the movable optical member with respect to the optical axis of the optical system to make both the optical axes parallel to each other. According to the above-described arrangement, it is possible to maintain the optical performance of the device or the apparatus at a high level without increasing the precision of constituent elements of mechanism for supporting the movable optical member.