To obtain an optical isolator which is low in price and of which the adhesion strength and the optical characteristics are secured.

The optical isolator having a casing, a polarizer 3, a Faraday rotator 4 and a magnet 6 as constitution members is characterized in that low melting point metal solder or low melting point glass solder is used for adhesion of the casing to the polarizer 3 and the casing to the magnet 6 and an organic adhesive is used for adhesion of the polarizer 3 to the Faraday rotator 4.