A buckle including a pair of members (4, 5) coupled to or separated from each other. The buckle includes a socket (10) and a plug (30) capable of being inserted into the socket and hooked in the socket in the state where the plug is inserted into a prespecified position. The socket is attached to a one member (5) in the pair. The plug has a pull section (33) in the direction intersectional to the plug inserting direction, and a mounting section (37) with the other member mounted thereon is provided on the pull section (33).