PURPOSE:To form the connected part of superior connection strength and current supplying characterstic by forming reduced diameter parts to the end parts of two wires to be connected, inserting the end parts into the specific connecting pipe and spot electrowelding the both end parts of the connecting pipe. CONSTITUTION:Beforehand, reduced diameter parts 3, 4 are formed to the trailing end part 1 of an old reel wire and the leading end part 2 of a new reel wire. At the time of connection, these end parts are butted and inserted into a connecting pipe 5 whose outside diameter is nearly equal to that of the wire. Next, when current is supplied while both end parts 6, 6 of the pipe are held by electrodes, the inside surface of the pipe and the reduced diameter parts of the wire are spot welded and are firmly connected. This method is advantageous for connection of particularly the fine wires of about 1mm. Even if the butt parts are not in close contact, current supplying characteristic is good.