The invention provides a window regulator that can be easily assembled and a jig for assembling it. The window regulator has a drum rotatable in the normal and reverse directions, an annular wire (71), a part of which is wrapped around the drum, guide members (81, 83, 91, 93) fitted to an inner panel and guiding the wire (71) so that the wire (71) is disposed in the lifting direction of window glass (53), slack prevention means for eliminating slack of the wire (71) by biasing the wire (71) in the direction of tensioning it, and window glass mounting means (101, 103) for mounting the window glass (53) on the wire (71), at portions along the lifting direction of the window glass (53). The window regulator further has a bracket (131) rotatably fitted to the inner panel, having the guide member (83), and guiding the guide member (83) to a place where the inner panel is mounted.