Axisymmetric polarization converter

In axially symmetric polarization conversion element 10 for converting incident light into axially symmetric polarized beam, it has a reflection portion 20 in the shape in which the optical axis direction of the cross-section of the Fresnel rhomb wavelength plate is rotated about an axis parallel to the optical axis, using the Fresnel reflection twice in the reflection section 20 for converting incident light into axially symmetric polarization beam PB.