Housing structure of an electronic control unit

Depending mounted facing the vehicle, will accumulate water in the breathing filter unit, it is impossible to adjust the pressure difference between the enclosure and the ambient air, the vehicle-body-based layout is limited. Further, in order to form a filter portion in the housing-side central portion, a lower surface and an upper surface electronic components on a substrate of the filter unit can not be mounted, the substrate size and the housing size increases. In addition, it increases the cost. Provided each of the respiratory passages of the face-to-face sandwiching the portion where the filter membrane was welded to the corner of the resin casing of an electronic control device mounted on a vehicle such as a control unit for engine control unit and the automatic transmission, the passage has a structure which is characterized in that connected internally.