The present invention relates to an optical isolator having a plurality of Faraday rotators with a structure, which allows an accurate and easy assembly.The optical isolator relating to the present invention, includes: an optical isolator unit having a plurality of optical elements which have Faraday rotators and birefringent crystal plates arranged on both sides of the each rotator; a plurality of magnets arranged on the circumference of the Faraday rotators for magnetizing the Faraday rotators; and a housing body arranged on the circumference of the plurality of magnets, the plurality of magnets being integrally formed, and the optical isolating unit being integrally fixed with the integrally formed magnets.