An optical isolator 1 element comprises a Faraday rotator 11 that rotates a polarization plane of light; a first polarizer of optical absorption type 12 arranged on one surface side of the Faraday rotator 11, the first polarizer 12 having a layer in which metal particles are distributed; and a second polarizer of optical absorption type 13 arranged on another surface side of the Faraday rotator 11, the second polarizer 13 having a metal particle layer in which metal particles are distributed in a density higher than the density of metal particles distributed in the metal particle layer of the first polarizer 12. The optical isolator 1 makes it possible to reduce a deterioration of isolation caused by occurring a reflected light reflected between the second polarizer 13 and the first polarizer 12.