A ferrule connection optical isolator with an optical fiber, wherein the
optical isolator includes a ferrule with at least one processed end
surface. The optical fiber consists of two kinds of materials and has a
concentric level difference between the materials. A small cylindrical
magnet having a size larger than the outer diameter of the level
difference portion but smaller than the outermost diameter of the ferrule
is connected to the level difference portion. A guide ring is inserted and
fixed in the magnet, and an optical element that consists of at least one
polarizer and at least one Faraday rotator is connected and fixed in the
guide ring.