PURPOSE: To provide the optical adapter which is small in number of parts, is inexpensive, permits easy connection of optical fibers with good workability, makes it possible to sufficiently obtain the accuracy of repetitive connection and has a structure which hardly generates connection loss by vibrations, etc.

CONSTITUTION: This optical adapter has split sleeves 11, a first main body 12A which consists of a cylindrical part 12a to be press fitted with one end side of the split sleeves 11 and a flange part 12aa formed in the cylindrical part 12a and is provided with a flange part 12af to be pressed with the split sleeves 11 and the first main body 12A provided with the fitting recessed part 12ad in the cylindrical part 12a, a second main body 12B which consists of a cylindrical part 12b to be inserted with the other end side of the split sleeves 11 and a flange part 12bb formed in the cylindrical part 12b and is provided with a flange 12bf to be pressed with the split sleeves 11 and a fitting projecting 12bd fit in into the fitting recessed part 12ad in the cylindrical part 12b and a screw 13 which fastens the first main body 12A and the second main body 12B.