An in-wheel driving device, the device comprising: a wheel bearing including a hub and an outer ring disposed outward of the hub in a radial direction; a speed reducer including a carrier coupled to a wheel; an annular sealing member disposed between the hub and the carrier and brought into close contact with the carrier to seal lubricant oil supplied into the speed reducer; and wheel bolts configured to couple the wheel and the carrier, wherein the wheel bolts pass through a plurality of wheel bolt holes formed in the carrier spaced apart from each other in a circumferential direction, wherein the sealing member is concentric with a first virtual circle passing through centers of the plurality of wheel bolt holes, and wherein the first virtual circle has a larger diameter than the sealing member such that the wheel bolts are located outward of the sealing member in the radial direction, wherein the carrier includes: a carrier body; and a carrier flange formed on an end portion of the carrier body in a direction from the wheel bearing toward the wheel bolts based on a direction of a central axis of the wheel bearing and configured to extend from the carrier body in the radial direction, the carrier flange having the wheel bolt holes formed therein, and wherein the carrier flange further includes a seal close-contact surface with which the sealing member is brought into close contact, the seal close-contact surface being formed inward of the wheel bolt holes in the radial direction, and wherein the in-wheel driving device further comprises: fastening bolts configured to couple the carrier and the wheel bearing, wherein the carrier flange includes a plurality of fastening holes through which the fastening bolts pass, the plurality of fastening holes being spaced apart from each other in the circumferential direction. a wheel bearing including a hub and an outer ring disposed outward of the hub in a radial direction; a speed reducer including a carrier coupled to a wheel; an annular sealing member disposed between the hub and the carrier and brought into close contact with the carrier to seal lubricant oil supplied into the speed reducer; and wheel bolts configured to couple the wheel and the carrier, wherein the wheel bolts pass through a plurality of wheel bolt holes formed in the carrier spaced apart from each other in a circumferential direction, wherein the sealing member is concentric with a first virtual circle passing through centers of the plurality of wheel bolt holes, and wherein the first virtual circle has a larger diameter than the sealing member such that the wheel bolts are located outward of the sealing member in the radial direction, wherein the carrier includes: a carrier body; and a carrier flange formed on an end portion of the carrier body in a direction from the wheel bearing toward the wheel bolts based on a direction of a central axis of the wheel bearing and configured to extend from the carrier body in the radial direction, the carrier flange having the wheel bolt holes formed therein, and wherein the carrier flange further includes a seal close-contact surface with which the sealing member is brought into close contact, the seal close-contact surface being formed inward of the wheel bolt holes in the radial direction, and a carrier body; and a carrier flange formed on an end portion of the carrier body in a direction from the wheel bearing toward the wheel bolts based on a direction of a central axis of the wheel bearing and configured to extend from the carrier body in the radial direction, the carrier flange having the wheel bolt holes formed therein, and wherein the carrier flange further includes a seal close-contact surface with which the sealing member is brought into close contact, the seal close-contact surface being formed inward of the wheel bolt holes in the radial direction, and wherein the in-wheel driving device further comprises: fastening bolts configured to couple the carrier and the wheel bearing, wherein the carrier flange includes a plurality of fastening holes through which the fastening bolts pass, the plurality of fastening holes being spaced apart from each other in the circumferential direction.