Herein disclosed is a window regulator for regulating a glass pane, which comprises a guide rail (2) including front and rear vertical parts (2d, 2e) and a horizontal part which extends between the front and rear vertical parts to constitute a generally U-shaped structure of the guide rail; front and rear holders (10) slidably guided by the front and rear vertical parts (2d, 2e) of the guide rail (2); a first structure securing each of the front and rear holders (10) to the window pane (9); a second structure for defining in the guide rail two cable guide grooves which extend throughout the entire length of the guide rail; two drive cables (12, 13) axially movably received in the respective cable guide grooves, the drive cables (12, 13) having given portions to which the front and rear holders are connected respectively; and drive means (16) mounted on a given portion of the guide rail (2) for axially moving the two drive cables (12, 13) in opposite directions.