The optical apparatus includes multiple reflective light modulators, an illumination optical system and multiple dichroic surfaces separating a light flux from the illumination optical system into multiple color lights to introduce them to the light modulators and combining the multiple color lights reflected by the light modulators. The optical system includes a condenser lens disposed between an area in which light source images are formed and the multiple reflective light modulators. The light modulators are arranged such that their long sides are parallel to a first section, and a condition of f/D1>f/D2 is satisfied where f represents a focal length of the condenser lens, D1 and D2 represent maximum effective widths of the areas in which the light source images are formed in the first section and in a second section parallel to an optical axis and orthogonal to the first section.