To provide a stackable chair which is comfortable for sitting in various sitting postures, attractive in appearance, very strong, flexible in use, and economical in manufacture.

This stackable chair has a frame with a tubular horizontal rod 18, and legs 121, 12r, 141, 15r and backrest supports 16l, 16r and selectively a simple substance casting FC including an armrest are received in the horizontal rod 18, and fitted to the respective ends of the horizontal rod by an integral connecting boss held in a suitable place by a connecting pin. A backrest support receives a backrest 50, and the backrest 50 is turned round a vot pin between the erect position energized by a spring and a rear upward gradient position. The range of inclining motion is limited by a stop in of the backrest and a stop groove of the backrest support. A seat 24 is fitted to the horizontal rod in a fixed position, or fitted to be inclined to the erect position.