A flap device for an internal combustion engine which includes a flow housing with a housing wall which delimits a flow-through duct. The flap device includes a shaft mounted in the flow housing, a flap body rotatably mounted on the shaft, an actuator for the shaft, and a pressure measurement point. The pressure measurement point is arranged in a duct section of the flow housing so that the flap body traverses the pressure measurement point when rotating, and in a region of the flow housing remote from the shaft when viewed in a circumferential direction of the housing wall. A flap surface of the flap body is directed towards the pressure measurement point and is curved so that, in each rotary position, a tangent arranged at the position of the curved flap surface having a shortest distance to an opposite wall surface of the flow housing is parallel thereto.