A hexahedron prism in which a first optical surface and a second optical surface opposed to each other are approximately parallel, the inner angles θ between the first optical surface and each of a third optical surface and a fourth optical surface opposed to each other are equal, a fifth optical surface and a sixth optical surface opposed to each other are configured inclining toward each other and the distance therebetween becomes narrow from the third optical surface to the fourth optical surface, and further, a light beam from a image display element enters through a first partial optical surface into the hexahedron prism, reflects inside the prism and is emitted through a second partial optical surface to an eye pupil of a user.