The present invention provides a friction welder of a buoy for fishing, the friction welder which provides a compact machine, can manufacture a middle-sized buoy and a large-sized buoy, and in which a fixing ring provided at an outer portion of the buoy enables a friction welding process of the buoy to be performed at an accurate position such that defects are prevented from being generated in the manufacturing process. The friction welder of the present invention, as a friction welder of a buoy for fishing, the friction welder which completes the buoy by thermal bonding two constituent members obtained by dividing a part into two parts and performing an injection molding process of the two parts, comprises: a machine body； a driving body which is installed in one side of the machine body and is driven by a hydraulic motor； a moving cart which moves toward an opposite side of the driving body along rails installed on the machine body, and a moving cart cylinder of which both ends are fixed to the machine body and which moves the moving cart； a housing which is installed in the moving cart； a driven shaft which is axially installed in the housing to be freely rotated, and which is moved by a pressurizing cylinder, and a driven body which is installed in the driven shaft oppositely to the driving body； a brake device which is electrically operated and installed in the moving cart to include a brake drum and a lining that are installed in the driven shaft； an operating switch which is electrically connected to the brake device and installed on the bottom of the machine body； an operation part which is installed in a lower side of the machine body and includes a hydraulic unit installed to provide hydraulic pressure to the hydraulic motor, the moving cart cylinder and the pressurizing cylinder, and a plurality of operating levers installed on the machine body； and a tool post which is movable in forward and backward and up and down directions and installed in the machin
