In an ECU in which a sensor IC and various engine control devices are mounted on a board in a case, the sensor IC has a pressure sensor element covered with mold resin having a pressure introduction hole extending outward from the pressure sensor element so as to open to an outer surface thereof. A cylindrical resilient member is disposed and resiliently deformed between an inner wall of the case and the outer surface of the mold resin so as to allow a pressure introduction inlet formed in the case to communicate with the pressure introduction hole and not to communicate with places where the engine control devices are mounted. The case of ECU is fixed to a surge tank so that a pressure introduction outlet formed in the surge tank communicates directly with the pressure introduction inlet.