PURPOSE: To check exactly the connection of an electric wire corresponding to each contact by providing a continuity piece on each contact of a presswelding punch and a press-welding connector, respectively, and operating a continuity detector in case of a pressure welding connection.

CONSTITUTION: A continuity checking piece 50 is attached to a pressure welding punch 21 and connected to an earth 52, and also a continuity piece 36 is formed as one body on each contact 34 of a pressure welding connector 3. A continuity checking circuit 54 is provided on a winding device 15 through a slip ring 53 so as to be connected electrically to the end part of electric wires 2A1W2An, and a continuity detector 55 and a power source 56 are placed on said circuit. In such constitution, when an electric wire group 2A and each contact 34 of the pressure welding connector 3 are pressure welded and connected by the pressure welding punch 21 and a pressure welding die 22, the continuity detector 55 operates if the pressure welding is good, and it does not operate in case of failure. Accordingly, the pressure welding state is checked exactly.