Abstract: An object of the present invention is to provide a seal structure being capable of preventing rain water and the like from entering the inside of a vehicle through a clearance between an engagement portion and an engagement hole portion. The seal structure S is for fixing a window regulator WR to an inner panel 1. The inner panel 1 is provided with an engagement hole portion 1H, and the window regulator WR comprises an engagement portion 7 being slidable with respect to the inner panel 1 and engaging with the engagement hole portion 1H, a sealing member 8 provided around the engagement portion 7, and a seal supporting portion 9 holding the sealing member 7 between the seal supporting member 9 and the portion of the inner panel 1 surrounding the engagement hole portion 1H.