The invention provides a zoom lens device that can include lens groups. A third
lens group (compensator lens group) can be disposed between two lens groups (a
second and a fourth lens groups) forming a variator lens group. The two lens groups
(the second and fourth lens groups) forming the variator lens group can be retained
by a common variator-lens frame and moved together. Accordingly, a zoom lens device,
an optical apparatus, and a projector can be provided in which, even when a plurality
of lens groups are assembled, degradation of optical characteristics due to decentering
between the lens groups can be prevented.
