The invention discloses a bending device for bending a flat rod. The bending device comprises a first stop rod, a rotary table and a rotating shaft. The rotary table is further provided with an annular ring groove. The rotary table is further fixedly connected with a second stop rod. A notch is further formed in the side face of the first stop rod. The bending device further comprises a limiting block located in the ring groove. A second gap used for allowing the flat rod to penetrate through is formed between any side face of the ring groove and the limiting block, and the width of the second gap can be adjusted. The rotary table is further fixedly connected with a rotary handle. The bending device is simple in structure and can be used for bending the flat rod at a construction site conveniently, bends of special dimensions can be bent according to the construction needs, and the purposes of reducing obtaining cost of the bends and avoiding secondary machining can be achieved. Meanwhile, the bending deformation direction of the flat rod can be well limited when the flat rod is bent, and the forming quality of products can be better improved.