To increase the lock force of an opening-closing member of a door of a furniture, such as a sideboard, to prevent the occurrence of a backlash, and to allow a smooth engaging and disengaging operation.

A body 1 is provided with a to-be-locked member 10 having a hook-form engaging part 11 and a lock member 20 having a hook-form engaging part 21 and a lever-form operation member 26 are arranged to an opening- closing member 2 in a manner to be integrally rotatably supported at the opening-closing member 2. Through rotation of the lock member 20, the engaging parts 11 and 21 are disengageably engaged with each other to increase a lock force. Further, a magnet 19 and a member 29 to be attracted are fixed at the opening-closing member 2, the magnet 19 and the member 29 to be attracted are removably attracted to each other, and a backlash is prevented from occurring. A cam-form extrusion part 22 is fixed at the lock member 20 and after the engaging parts 11 and 21 are released from engagement through rotation of the lock member 20, a member 17 to be pressed on the body 1 side is pressed by a press part 24, through separation of the magnet 19 and the member 29 to be attracted from each other, an attraction state is released, and engaging and disengaging operation is smoothed.