A positioning jig for a spot-welding electrode includes an attaching portion for temporarily attaching to a workpiece. A positioning portion of the jig is disposed in parallel to a central axis of the attaching portion and spaced from the central axis. The positioning portion has an imaginary central axis coinciding with the central axis of the attaching portion. With the attaching portion attached to that part of a workpiece surface which is to be spot welded, the electrode is set on the central axis of the attaching portion. An inclination of the electrode is corrected to make the electrode stand parallel to the positioning portion such that, even when the workpiece surface is curved, the electrode can be positioned perpendicularly to the workpiece surface part to be spot welded.