A polarization conversion element comprising: a phase reversal element (2, 2') that reverses phase of a part of incident light having a prescribed wavelength; and a polarization plane rotation element that converts linear polarization having the prescribed wavelength to radial polarization, disposed along an optical axis; wherein the polarization plane rotation element comprises a liquid crystal layer containing liquid crystal molecules, and two first transparent electrodes (31, 33; 32, 34) disposed in opposition to each other so as to sandwich the liquid crystal layer; wherein the liquid crystal layer has a plurality of regions (30a to 30h) arranged along circumferential direction with a first intersection point (C 1) of the polarization plane rotation element and an optical axis as a center, alignment direction of the liquid crystal molecules contained in each of the plurality of regions being different from each other; wherein, when an electric voltage in accordance with the prescribed wavelength is applied between the two first transparent electrodes, each of the plurality of regions of the liquid crystal layer rotates polarization plane of a component of the linear polarization passing the region in accordance with the alignment direction of the liquid crystal molecules contained in the region such that the polarization plane becomes parallel to radial direction with the first intersection point as the center; and wherein the phase reversal element (2, 2') has first annular portions and second annular portions alternately disposed along radial direction with a second intersection point (C 0) of the phase reversal element and the optical axis as a center, and reverses the phase of the linear polarization or the radial polarization incident on the first annular portions relative to the phase of the linear polarization or the radial polarization incident on the second annular portions. a phase reversal element (2, 2') that reverses phase of a part of incident light having a prescribed wavelength; and a polarization plane rotation element that converts linear polarization having the prescribed wavelength to radial polarization, disposed along an optical axis; wherein the polarization plane rotation element comprises a liquid crystal layer containing liquid crystal molecules, and two first transparent electrodes (31, 33; 32, 34) disposed in opposition to each other so as to sandwich the liquid crystal layer; wherein the liquid crystal layer has a plurality of regions (30a to 30h) arranged along circumferential direction with a first intersection point (C 1) of the polarization plane rotation element and an optical axis as a center, alignment direction of the liquid crystal molecules contained in each of the plurality of regions being different from each other; wherein, when an electric voltage in accordance with the prescribed wavelength is applied between the two first transparent electrodes, each of the plurality of regions of the liquid crystal layer rotates polarization plane of a component of the linear polarization passing the region in accordance with the alignment direction of the liquid crystal molecules contained in the region such that the polarization plane becomes parallel to radial direction with the first intersection point as the center; and wherein the phase reversal element (2, 2') has first annular portions and second annular portions alternately disposed along radial direction with a second intersection point (C 0) of the phase reversal element and the optical axis as a center, and reverses the phase of the linear polarization or the radial polarization incident on the first annular portions relative to the phase of the linear polarization or the radial polarization incident on the second annular portions.