An optical element (1, 1X, 1Y, 1A, 1B) comprising: a first layer; and a second layer (A2, A2Y) that faces the first layer, wherein the first layer includes a plurality of first structural bodies that each have optical anisotropy, wherein plural first structural bodies of said plurality of structural bodies differ from one another in direction of orientation, wherein the second layer includes a plurality of second structural bodies each forming a helix, each of the second structural bodies being arranged to reflect first light having a wavelength in a band according to the pitch of the helix and the refractive index of the second structural bodies and having circular polarization or elliptical polarization in a direction of circulation that is the same direction as a helical direction of the helix of the second structural body, wherein in reflection of the first light entering from the first layer, the second layer is arranged to reflect the first light while substantially maintaining a polarisation state of the light in the sense that a direction of phase change of the first light relative to a propagation direction of the first light does not vary between at incidence and at the reflection, and wherein the first layer is arranged to change, according to directions of orientation of the first structural bodies, a wavefront of the first light at output from the first layer toward the second layer relative to a wavefront of the first light at incidence to the first layer from outside of the first layer by differentiating spatial phases of a plurality of light fluxes output from the respective first structural bodies according to the directions of orientation of the respective first structural bodies, and is arranged to change, according to the directions of orientation of the first structural bodies, the wavefront of the first light at output from the first layer toward the outside of the first layer relative to a wavefront of the first light at incidence to the first layer from the second layer by differentiating the spatial phases of the light fluxes output from the respective first structural bodies according to the directions of orientation of the first structural bodies. a first layer; and a second layer (A2, A2Y) that faces the first layer, wherein the first layer includes a plurality of first structural bodies that each have optical anisotropy, wherein plural first structural bodies of said plurality of structural bodies differ from one another in direction of orientation, wherein the second layer includes a plurality of second structural bodies each forming a helix, each of the second structural bodies being arranged to reflect first light having a wavelength in a band according to the pitch of the helix and the refractive index of the second structural bodies and having circular polarization or elliptical polarization in a direction of circulation that is the same direction as a helical direction of the helix of the second structural body, wherein in reflection of the first light entering from the first layer, the second layer is arranged to reflect the first light while substantially maintaining a polarisation state of the light in the sense that a direction of phase change of the first light relative to a propagation direction of the first light does not vary between at incidence and at the reflection, and wherein the first layer is arranged to change, according to directions of orientation of the first structural bodies, a wavefront of the first light at output from the first layer toward the second layer relative to a wavefront of the first light at incidence to the first layer from outside of the first layer by differentiating spatial phases of a plurality of light fluxes output from the respective first structural bodies according to the directions of orientation of the respective first structural bodies, and is arranged to change, according to the directions of orientation of the first structural bodies, the wavefront of the first light at output from the first layer toward the outside of the first layer relative to a wavefront of the first light at incidence to the first layer from the second layer by differentiating the spatial phases of the light fluxes output from the respective first structural bodies according to the directions of orientation of the first structural bodies.