Vacuum diffusion welding device

The invention discloses a vacuum diffusion welding device which comprises a furnace body, a vacuumizing assembly, a mounting table, an upper pressing head and a plurality of contact rods. A pressure cavity is formed in the upper pressure head, and a plurality of contact rods are arranged on the bottom surface of the upper pressure head in a sliding manner; during use, the contact rod can extend out through pressure in the pressure chamber, so that the contact rod is in contact with the top surface of a workpiece to apply pressure to the workpiece. As the plurality of contact rods are arranged in a sliding manner, the lower ends of the plurality of contact rods can automatically adapt to the shape of the top surface of the workpiece. Meanwhile, the contact rod outside the workpiece can limit the workpiece on the side face of the workpiece, stability of the workpiece is guaranteed, and dislocation of the welded workpiece caused by movement of the workpiece due to vibration or other factors is avoided. And the u