The utility model discloses a metal strip bending device, relating to construction machinery. The metal strip bending device comprises two parallel support plates(2) which are fixedly connected on soleplate(1); two positioning pins(3) are fixedly connected between the two support plates(2); a circular arc press head(4) is arranged between the two positioning pins(3); the front end of the press head(4) reciprocates along the perpendicular bisector between the two positioning pins(3); the press head(4) and the two support plates(2) are in clearance fit; a driving mechanism is arranged at the rear end of the press head(4); and the circular arc press head(4) and the support plates are in slip connection. The metal strip bending machine is simple in structure and saves time and labor and is applicable at the construction site; and the angle of the R inner arc of the metal strip material (5) to be bent can be controlled by controlling the distance under the push of the driving mechanism(8). The metal strip bending device is particularly suitable for flat strip metal materials like sheet metal; a plurality of metal strips can be bent at the same time without the defect that the bent part deviates from the plane of the strip material; and the bent material is uniform, standardized and good in effect.