An intake device includes: an intake port; and a valve body which is disposed in the intake port and is rotated around a rotation axial line between an open/closed position, in which the valve body includes a valve body main body made of a resin, an elastically deformable seal portion formed to extend along an outer circumferential portion of the valve body main body, and a projection which is provided at a surface part adjacent to a region in which the seal portion is formed in the valve body main body, and has a shape that gradually becomes tapered toward a tip end side.