Electronic Control Device

Provided is an electronic control device capable of suppressing outflow of a sealing material to the outside and reducing defective attachment of a bracket. The electronic control device to be attached to a bracket includes a cover (first housing) and a case (second housing) fitted to the cover The cover (first housing) includes a first flange F and a first groove portion filled with a sealing material The case (second housing) includes a second flange F overlapping the first flange F, and a case protrusion (protrusion) fitted to the first groove portion and embedded in the sealing material The first flange F of the cover (first housing) has a second groove portion present at a position that is closer to the outside than the first groove portion is.