To attach a reflector wherein a certain reflection effect is achieved for light of irradiated vehicles without breaking an appearance of posts of guard fences installed along a roadside and a boundary line between the road and the sidewalk, or a park, a promenade and a bicycle track by attaching a reflecting sheet, etc., and without deflecting and dropping out by external force and loosening on bolts.

A joint 1, wherein effective visibility at nighttime is obtained, is so constituted that locking parts 13 are formed on a ring body 12 formed a through hole 11 for inserting an end part of a beam 5 by interposing between a post 3 and the beam 5, and are locked in a beam hole 31 opened in a side of the post 3. Furthermore, a reflector 21 is attached on the ring body 12, and is attached opposing a centerline 8 of reflection to light reached from a vehicle.