A liquid crystal prism element includes: a first prism array; a second prism array arranged so as to face the first prism array; and a liquid crystal layer provided between the first and second prism arrays. The first prism array is composed of a plurality of first prisms that have ridge lines extending in a Y axis direction and are arranged so as to be spaced apart from each other at predetermined intervals in an X axis direction The second prism array is composed of second prisms that have ridge lines extending in the Y axis direction and are arranged so as to be spaced apart from each other at predetermined intervals in the X axis direction. Each first prism has an inclined surface facing a center side of the liquid crystal layer. Each second prism has an inclined surface facing the center side of the liquid crystal layer.