A window regulator comprises a front guide rail installed in a front portion of a door and extending upward and downward; a rear guide rail installed in a rear portion of the door and extending upward and downward; a front carrier unit fixed to a lower front portion of the window pane and slidably engaged with the front guide rail through a first mechanism; and a rear carrier unit fixed to a lower rear portion of the window pane and slidably engaged with the rear guide rail through a second mechanism. The first mechanism is constructed to permit a pivotal movement of the front carrier unit about an imaginary axis that extends along the front guide rail. The second mechanism has a with a channel construction includes a slider on the rear carrier unit that is slidably received in a channel construction of the rear guide rail. The construction has a generally C-shaped cross section with its open side facing to the outside an exterior of the door when the door is mounted on a vehicle.