To provide a reflection type polarizing modulation element capable of using a circularly polarized light or a linearly polarized light and modulating these polarized states of the light without using a radiation light source even in a vacuum ultraviolet region where no transmission type polarizing element can be used.

In a reflection type polarizing modulation element including a polarizer part which puts light from a light source into an approximately linearly polarized state and a phase element part which puts approximately linearly polarized light from the polarizer part into approximately circularly polarized light or an approximately linearly polarized state, the polarizer part includes a metal mirror, and puts incident light into the approximately linearly polarized state by the reflection of the metal mirror so as to be input to the phase element part, and the phase element part is provided with a pair of planar mirrors disposed in such a manner that the incident light to the phase element part and an optical axis of a transmitted light match each other.