Afforded is an optical element holder allowing high-accuracy stereo images to be taken. The holder includes: a rectangular parallelepiped beam splitter (5) having a rectangular incident surface (12); a pair of mutually opposing holding members (8) into which end portions of the beam splitter along the x-axis are fitted; and a base portion (9) and screws (10) that press on the holding members (8), drawing them toward each other. Each of the holding members (8) has a flat surface portion covering a lateral surface of the beam splitter (5), and a peripheral wall portion standing along the periphery of the flat surface potion. A width, along the x-axis, whereby the peripheral wall portion and a first light-exit surface opposing the incident surface (12) of the beam splitter (5) overlap is greater than a width, in the same orientation, whereby the incident surface (12) and the peripheral wall portion overlap.