An in-wheel motor comprising: a circular rim having an integrated structure and one open side surface to which a tire is coupled by being wrapped around an outer ring thereof and a shaft is connected by passing through a center thereof; a motor assembly which is disposed in an inner portion of the rim and includes a stator connected to the shaft and a rotor disposed to be wrapped around the stator and configured to rotate; a cover coupled to cover said one open side surface of the rim and configured to be assembled with the rim and to seal the inner portion of the rim; and a lead-out wire entry/exit portion waterproof structure configured to seal an entry/exit portion for a lead-out wire connected to supply power from outside of the in-wheel motor to the inner portion of the rim via a hollow portion of the shaft, wherein the lead-out wire entry/exit portion waterproof structure includes an elastic stopper, to which the lead-out wire is connected to pass through a center thereof and which is configured to be elastically contracted after being inserted into the hollow portion of the shaft in an axial direction of the shaft and seal between the hollow portion of the shaft and the lead-out wire, and a stopper fixing body fastened to the shaft and configured to block the hollow portion of the shaft at a portion where the hollow portion of the shaft starts, and configured to press the elastic stopper in the axial direction of the shaft toward the inside of the hollow portion of the shaft so that the elastic stopper is inserted and fixed inside the hollow portion of the shaft, wherein the elastic stopper has conical shape forming a conical surface whose diameter gradually increases from one end portion, which is inserted into the hollow portion of the shaft first, toward the other end portion, which is inserted into the hollow portion of the shaft later due to being pressed by the stopper fixing body, and the conical surface is formed around a circumference of the elastic stopper. a circular rim having an integrated structure and one open side surface to which a tire is coupled by being wrapped around an outer ring thereof and a shaft is connected by passing through a center thereof; a motor assembly which is disposed in an inner portion of the rim and includes a stator connected to the shaft and a rotor disposed to be wrapped around the stator and configured to rotate; a cover coupled to cover said one open side surface of the rim and configured to be assembled with the rim and to seal the inner portion of the rim; and a lead-out wire entry/exit portion waterproof structure configured to seal an entry/exit portion for a lead-out wire connected to supply power from outside of the in-wheel motor to the inner portion of the rim via a hollow portion of the shaft, wherein the lead-out wire entry/exit portion waterproof structure includes an elastic stopper, to which the lead-out wire is connected to pass through a center thereof and which is configured to be elastically contracted after being inserted into the hollow portion of the shaft in an axial direction of the shaft and seal between the hollow portion of the shaft and the lead-out wire, and a stopper fixing body fastened to the shaft and configured to block the hollow portion of the shaft at a portion where the hollow portion of the shaft starts, and configured to press the elastic stopper in the axial direction of the shaft toward the inside of the hollow portion of the shaft so that the elastic stopper is inserted and fixed inside the hollow portion of the shaft, wherein the elastic stopper has conical shape forming a conical surface whose diameter gradually increases from one end portion, which is inserted into the hollow portion of the shaft first, toward the other end portion, which is inserted into the hollow portion of the shaft later due to being pressed by the stopper fixing body, and the conical surface is formed around a circumference of the elastic stopper.