Abstract: The present invention provides spectacles for which lens replacement is simple, and replacement lens portability is excellent, and which is capable of reliably mounting and fastening a lens to a frame without a risk of damaging a lens. The present invention has a lens-side-connecting member 3 for mounting lens 2 detachably to a frame portion 1, which is constituted by a member separate from lens 2 and is fixed to the edge portion of the lens 2, and a frame-side-connecting member 120, which is disposed on the above-mentioned frame portion 1 for mounting the above-mentioned lens 2 detachably to the above-mentioned frame portion 1 by connecting the same detachably to the above-mentioned lens-side-connecting member 3.

Abstract: An optical isolator not dependent on the plane of polarization of an incident beam and does not allow the plane of polarization to change on the outgoing side. The optical isolator comprises a first parallel flat double refractive crystal substance; a first Faraday rotor for rotating the plane of polarization of a beam; a second parallel flat double refractive crystal substance; a second Faraday rotor for rotating the plane of polarization in a direction opposite to that in which said first Faraday rotor rotates the plane of polarization; a third parallel flat double refractive substance; a fourth parallel flat double refractive substance; and permanent magnets for magnetizing the Faraday rotor and second Faraday rotors. Since a pair of Faraday rotors for rotating the plane of polarization in opposite directions, the plane of polarization on the incident side does not change on the outgoing side.