To easily attain miniaturization of an optical mechanism and further miniaturization compactification of an image display apparatus while assuring necessary and sufficient optical characteristics (optical performance) around a dichroic prism.

A light coupling body includes a dichroic prism main body part 2, which has a pair of dichroic filters Fr, Fb and three incident surfaces 2r, 2g, 2b where respective element rays Lr, Lg, Lb are respectively made incident and which couples and emits three colors of element rays Lr, Lg, Lb that are made incident from respective incident surfaces 2r, 2g, 2b. Further Fresnel lens parts 3r, 3g, 3b, which respectively convert respective incident element rays Lr, Lg, Lb to parallel rays Lrp, Lgp, Lbp and make them incident on respective incident surfaces 2r, 2g, 2b of the dichroic prism main body part 2, are installed integrally with the dichroic prism main body part 2.