The utility model discloses a round pin axle material U type device that bends, including last membrane module and lower membrane module, upward the membrane module is equipped with and is used for the application of force to push down the terrace die of round pin axle material, lower membrane module is equipped with and is used for spacing roll extrusion to sell a gyro wheel mechanism of material, be used for a location support round pin positioning mechanism who expects and do positioning mechanism carries ammunition feed nature buffer function's spring buffer gear, and when bending the operation, middle position portion has been predetermine to round pin axle material, round pin axle material passes through middle position portion places the location positioning mechanism is last, the terrace die moves down the application of force and pushes down round pin axle material, under spring buffer gear's elastic reaction, round pin axle material pressurized moves down and bears the roll extrusion effort of gyro wheel mechanism makes round pin axle material bends into the U type. The U type that realizes round pin axle material through this device bends, and the both sides symmetry isgood through about the fashioned part that bends, the steady quality.