A spacer members is placed between a lens that is located at the lowermost end among a plurality of lenses and a parallel flat plate that is placed below the lens, and the lens is made to support by suspension the parallel flat plate by sucking a part of the lens and the parallel flat plate. Accordingly, the spacer member does not need to be larger than the parallel flat plate and the space in the vicinity of the parallel flat plate can be secured, compared with the case where a holding mechanism that holds the parallel flat plate by grasping it is employed. Further, since the parallel flat plate is not grasped, deformation of the parallel flat plate can be avoided, which can suppress occurrence of aberration in a projection unit.