An intake pipe for intake gas of an internal combustion engine has an intake pipe channel and a flap unit with a flap shaft and a flap fixedly arranged on the flap shaft. The flap unit alternatingly opens or closes the intake pipe channel. A hollow insert body is disposed in the intake pipe channel, wherein the flap unit is arranged in the insert body and the flap is positioned in a hollow interior of the insert body. The insert body has opposite end faces and the opposite end faces are open. The flap shaft extends through opposite walls of the insert body in a radial direction relative to an insert body axis of the insert body. The insert body is rotatable on the flap shaft. A radial inner circumferential side of the insert body widens toward at least one of the open end faces.