A varifocal lens comprising: a first phase plate comprising a plurality of first phase conversion elements, at least some of the plurality of first phase conversion elements having different sizes from each other; and a second phase plate comprising a plurality of second phase conversion elements, at least some of the plurality of second phase conversion elements having different sizes from each other, wherein the first phase plate and the second phase plate face each other along an optical axis and are movable relative to each other in a direction perpendicular to the optical axis to create displacement between the first phase plate and the second phase plate, and the plurality of first phase conversion elements and the plurality of second phase conversion elements are configured so that light transmitted through the first phase plate and the second phase plate is focused on different positions on the optical axis depending on the displacement between the first phase plate and the second phase plate; characterized in that the first phase plate comprises a first region in which the plurality of first phase conversion elements are arranged and a second region in which the plurality of first phase conversion elements are arranged differently from the arrangement in the first region, and the second phase plate comprises a third region in which the plurality of second phase conversion elements are arranged and a fourth region in which the plurality of second phase conversion elements are arranged differently from the arrangement in the third region, and wherein the first phase plate and the second phase plate are configured so that the first region and the third region face each other and the second region and the fourth region face each other; wherein the plurality of first phase conversion elements and the plurality of second phase elements are configured so that the first region and the third region collectively function as a first lens element and the second region and the fourth region collectively function as a second lens element; wherein the first lens element and the second lens element have different focal lengths from each other at a certain displacement between the first phase plate and the second phase plate. a first phase plate comprising a plurality of first phase conversion elements, at least some of the plurality of first phase conversion elements having different sizes from each other; and a second phase plate comprising a plurality of second phase conversion elements, at least some of the plurality of second phase conversion elements having different sizes from each other, wherein the first phase plate and the second phase plate face each other along an optical axis and are movable relative to each other in a direction perpendicular to the optical axis to create displacement between the first phase plate and the second phase plate, and the plurality of first phase conversion elements and the plurality of second phase conversion elements are configured so that light transmitted through the first phase plate and the second phase plate is focused on different positions on the optical axis depending on the displacement between the first phase plate and the second phase plate; characterized in that the first phase plate comprises a first region in which the plurality of first phase conversion elements are arranged and a second region in which the plurality of first phase conversion elements are arranged differently from the arrangement in the first region, and the second phase plate comprises a third region in which the plurality of second phase conversion elements are arranged and a fourth region in which the plurality of second phase conversion elements are arranged differently from the arrangement in the third region, and wherein the first phase plate and the second phase plate are configured so that the first region and the third region face each other and the second region and the fourth region face each other; wherein the plurality of first phase conversion elements and the plurality of second phase elements are configured so that the first region and the third region collectively function as a first lens element and the second region and the fourth region collectively function as a second lens element; wherein the first lens element and the second lens element have different focal lengths from each other at a certain displacement between the first phase plate and the second phase plate.