A Faraday rotator in which the isolation function based on a temperature rise is not deteriorated even when the Faraday rotator is used for a high output laser of not smaller than 1W output at a wavelength of not larger than 1.1 μm includes sapphire crystals or rutile crystals bonded as radiation substrates to the incident side and outgoing side of a bismuth substituted type rare earth metal iron garnet crystal (RIG) film, the thickness of the RIG film being not smaller than 130 μm and not larger than 200 μm.