Aspects of the invention can provide a projector can include an illumination device that outputs illumination light, a color separation system that divides the illumination light output from the illumination device into blue light, red light, and green light and guides the blue light, red light, and green light to first to third optical paths, respectively, and first to third light modulation devices disposed in the first to third optical paths to be illuminated by the blue light, red light, and green light. In the projector, a distance from the illumination device to the third optical modulation device can be longer than a distance from the illumination device to the first optical modulation device and a distance from the illumination device to the second optical modulation device, a relay system having a first lens disposed at the light incident side, a second lens disposed at the light exit side, and a third lens disposed between the first and second lenses can be provided in the third optical path. The third lens can have a reference part as reference when the third lens is positioned along an optical axis of the third optical path, and the color separation system has a fixing part that positions the third lens in the third optical path by locking the reference part and can adjust the position of the third lens in the optical axis direction in a step-by-step manner by a combination way when the reference part is locked in the fixing part.