PURPOSE: To elevate efficiency of a teaching work, by providing a pilot lamp on a torch or its vicinity between a welding start point and a welding stop point.

CONSTITUTION: Teaching of position information is executed by following a weld line of a work from a teaching box, and also the welding work condition is taught from a keyboard switch of a control panel 2. After the teaching has ended in a general way, checking is executed by operating a torch at a low speed by a taught pass and a welding condition. In this case, when the torch is moved to a welding start point, a relay 31 is turned on by a welding start command, and a pilot lamp 33 turns on or flickers by a closed circuit of a contact 32. Also, when the torch is moved to a welding stop point, the relay 31 is turned off, said operation is reversed, and the pilot lamp turns off.