An automatic picking fixture device: a fixture locked with a mechanical arm and includes a coupling orifice, a motor, a rotor, and a gear. The fixture includes four elongated orifices and two movable holders. The two movable holders have four through orifices corresponding to the gear, four passing orifices, and two toothed sections received in the four through orifices and meshing with and driving the gear. The four passing orifices of the fixture is configured to lock with the four pneumatic cylinders or four servo motors, and the four pneumatic cylinders or the four servo motors are configured to push four jaws outward or inward, the four jaws include four symmetrical clamping grooves configured to clamp at least one material. The four racks are fixed on the top of the fixture, and a respective rack has two rollers rolling along a respective elongated orifice.