An illumination device has a board, a plurality of light emitting elements that are mounted on the board, the plurality of light emitting elements being disposed such that a light irradiation direction of each light emitting element becomes substantially perpendicular to the board, and a plurality of lenses. Each of the plurality of lens is paired with one of the plurality of light emitting elements. A relative positional relationship between the light emitting element and the lens in each pair varies according to a position on the board in which the corresponding light emitting element is disposed.