According to one embodiment, a liquid crystal optical element includes first and second substrate units, a liquid crystal layer, and spacers. The first substrate unit includes a first substrate and first electrodes. The first substrate has a first major surface. The first electrodes are provided on the first major surface, extend along a first direction, and have a first width in a second direction perpendicular to the first direction. The second substrate unit includes a second substrate and an opposing electrode. The second substrate has a second major surface opposed to the first major surface. The opposing electrode is provided on the second major surface. The liquid crystal layer is provided between the first and second substrate units. The spacers are in contact with the liquid crystal layer. A diameter of each spacer is larger than the first width.