A pair of push plates (11, 12) are slidably mounted in a housing (3) so as to be moved in a lateral direction with respect to a longitudinal direction of a personal adornment band (2), one of the push plates (11) has an upper arm (15) having a thickness of an upper half thickness of the push plate, the other push plate (12) has a lower arm (16) having a thickness of a lower half thickness of the push plate, upper and lower arms are overlapped with each other, and a pair of return springs (13) are provided between the push plates for urging each push plate in an outward direction. A cover (4) has a lock pin (21) secured to the underside thereof to be engaged with engaging hooks (20, 20c) of the push plates. In a coupling state of the buckle (1), an engaging rod (23a) provided on a connecting link (23) of an end of the personal adornment band is held by the cover and the housing which are locked each other. When the push plates are pushed at the same time, the engaging hooks are disengaged from the lock pin of the cover, so that the cover is opened and the connecting link is disconnected from the housing.