FRICTION WELDING MACHINE

PROBLEM TO BE SOLVED: To provide a friction welding machine, wherein welding can be carried out with high quality and high strength in a short time particularly when a base metal is composed of a thin sheet by carrying out the welding under an optimum condition through monitoring the welding condition. SOLUTION: A friction welding machine body 2 comprises; a cylinder 24; a rotary shaft which penetrates through the cylinder 24 having a welding member S such as a stud and the like at the tip end, and rotates by an oil hydraulic motor 21; and a piston which is engaged in the cylinder 24 and moves the rotary shaft. A rotation sensor 4 which detects the rotation number of a rotary shaft rotated by an oil hydraulic motor 21, a distance sensor 5 which detects the moving distance of the rotary shaft, and a pressure sensor 6 which detects the pressure of hydraulic operating fluid acting to the piston, are installed for fixing the friction welding machine body 2 to a frame 3 as well as for monitoring the welding status.