A flap device for an internal combustion engine includes a flow housing comprising a flow channel, an actuating shaft, a flap body arranged on the actuating shaft in the flow channel, a housing bore arranged in the flow housing, a lever fixed on the actuating shaft, a bearing bush arranged in the housing bore, and a sealing disk comprising a surface which is at least partially spherically shaped. The housing bore has the actuating shaft protrude outwards therethrough. The lever comprises a rear wall. The bearing bush has the actuating shaft mounted therein. The surface rests under tension against the rear wall of the lever.