A polarizing element is disclosed which includes a smooth glass substrate and a polarization layer formed thereon, the polarization layer having polarization characteristics for the incident light. The polarization layer is made of a carbon-based substance including carbon atoms. The carbon atoms are continuously connected via carbon-carbon double bonds having [pi] electron clouds. The [pi] electron clouds have average continuous distance of 100 nm or more in a longitudinal direction and have an average continuous distance less than 50 nm in a transverse direction. The carbon-based substance is formed in such a way that a plurality of the [pi] electron clouds have longitudinal directions which are in parallel along the glass-substrate surface.