A chair, comprising a load-supporting body, the load-supporting body including: a base plate (13, 113, 213, 313) constituting a framework; a cushion material arranged on a front surface side of the base plate; an upholstery material stretched to cover at least an outside surface of the cushion material and an outer peripheral edge of the base plate; and a tightening cord inserted through a peripheral edge of the upholstery material and tightened to allow end parts to be tied together on a rear surface side of the base plate in a state in which the upholstery material has covered the outside surface of the cushion material and the outer peripheral edge of the base plate, wherein the base plate (13, 113, 213, 313) is provided with first locking means for restricting displacement of the tightened tightening cord in a base-plate center direction, and second locking means for restricting displacement of the tightened tightening cord in a base plate outward direction, the first locking means includes a first side wall (24, 124) protruding from a rear surface of the base plate to a rear side, and a first protruding wall (26, 126, 226, 326) protruding in an outward direction of the base plate from the vicinity of a protruding end of the first side wall, the second locking means includes a second side wall (25, 125) protruding from the rear surface of the base plate to the rear side, and a second protruding wall (27, 127, 227, 327) protruding in an inward direction of the base plate from the vicinity of a protruding end of the second side wall; and the first protruding wall (24, 124) and the second protruding wall (25, 125) are arranged so as to be separated from each other in a direction in which the tightening cord extends, and to be adjacent to each other characterized in that: a recessed groove that is continuous in a circumferential direction of the base plate is formed in the rear surface of the base plate, the first side wall (24, 124) is an inside wall of the recessed groove, and the second side wall (25, 125) is an outside wall of the recessed groove. a base plate (13, 113, 213, 313) constituting a framework; a cushion material arranged on a front surface side of the base plate; an upholstery material stretched to cover at least an outside surface of the cushion material and an outer peripheral edge of the base plate; and a tightening cord inserted through a peripheral edge of the upholstery material and tightened to allow end parts to be tied together on a rear surface side of the base plate in a state in which the upholstery material has covered the outside surface of the cushion material and the outer peripheral edge of the base plate, wherein the base plate (13, 113, 213, 313) is provided with first locking means for restricting displacement of the tightened tightening cord in a base-plate center direction, and second locking means for restricting displacement of the tightened tightening cord in a base plate outward direction, the first locking means includes a first side wall (24, 124) protruding from a rear surface of the base plate to a rear side, and a first protruding wall (26, 126, 226, 326) protruding in an outward direction of the base plate from the vicinity of a protruding end of the first side wall, the second locking means includes a second side wall (25, 125) protruding from the rear surface of the base plate to the rear side, and a second protruding wall (27, 127, 227, 327) protruding in an inward direction of the base plate from the vicinity of a protruding end of the second side wall; and the first protruding wall (24, 124) and the second protruding wall (25, 125) are arranged so as to be separated from each other in a direction in which the tightening cord extends, and to be adjacent to each other characterized in that: a recessed groove that is continuous in a circumferential direction of the base plate is formed in the rear surface of the base plate, the first side wall (24, 124) is an inside wall of the recessed groove, and the second side wall (25, 125) is an outside wall of the recessed groove.