To provide a seal structure for a vehicle door that can prevent rainwater or the like from infiltrating into the inside of a vehicle from a gap between an engaging part of a window regulator and an engaging hole part of an inner panel.

In a seal structure S presented in this invention, a window regulator WR that has a carrier plate 2, a guide rail 3, a direction changing member 4 provided at one end of the guide rail 3, a driving part 5 and a wire 6 stretched between the carrier plate 2 and the driving part 5 is fixed to an inner panel 1 of a vehicle. The inner panel 1 is provided with an engaging hole part 1H, and the window regulator WR further includes an engaging part 7 that is slidable to the inner panel 1 and engaged with the engaging hole part 1H, a seal body 8 provided around the engaging part 7 and a seal supporting part 9 that holds the seal body 8 between the supporting part 9 and the portion around the engaging hole part 1H in the inner panel 1 when the engaging part 7 is engaged with the engaging hole part 1H.