PURPOSE: To lessen the influence of production error on luminous flux splitting element and to inexpensively produce a luminous flux splitting element by arranging luminous flux splitting films and adhesive layers in such a manner that the luminous flux which is first made incident on the luminous flux splitting element and split there before being transmitted through the adhesive layers.

CONSTITUTION: The luminous flux L which is made incident from an incident surface 19 and passes the inside of optical parts 13 is transmitted through the adhesive layer 18a in the luminous flux splitting film 17a and is split into the exit luminous flux L1 advancing in and the same direction as the direction of the luminous flux L and the reflected luminous flux L1' before being transmitted through the adhesive layer 18a. This luminous flux L1' is split into the exit luminous flux L2 emitted by reflection and the luminous flux L2' being transmitted through the adhesive layer 18b and advancing in the same direction as the luminous flux L1' in the luminous flux splitting film 17b before being transmitted through the next adhesive layer 18b. Further, the luminous flux L2' is split into the exit luminous flux L3 emitted by reflection and the luminous flux L3' being transmitted through the adhesive layer 18c and advancing in the same direction as the luminous flux L2' in the luminous flux splitting film 17c before being transmitted through the next adhesive layer 18c. The luminous flux L3' is totally reflected by the reflection film 17d and is emitted as the exit luminous flux L4.