The high frequency welder includes frame with two parallel tracks, two carriages on the tracks, HF heater with inducing heating coil on the carriage, fixture for clamping the welding tool and in the position corresponding to the inducing heating coil, and reducing motor to rotate the fixture. The high frequency welder of the present invention may be used to replace available manual brazing machine and has the advantages of high production efficiency, stable welding quality, low cost and low labor strength. In addition, the fixture under the driving of the motor can rotate the workpiece continuously to homogenize the welding material filled in the weld seam, resulting in high welding quality.