A relay optical system exhibits an action of deflecting light with respect to passing luminous flux as a result of being provided with a light deflection member, and thus a cross-section of the luminous flux can be adjusted to a state of having an appropriate size (enlarged size), that is, a state in which an image is not completely formed but is blurred, at image formation positions of color modulation light valves. Therefore, it is possible to form a favorable image by minimizing moire.