The invention provides a structure for attaching the main body and components of a vehicle-mounted electronic device, capable of increasing the size of an operation panel and a monitor for the electronic device stored in a vehicle-mounted electronic device storage section. In a first phase of the invention, in a structure for attaching a vehicle-mounted electronic device by fixing a vehicle-mounted electronic device to a vehicle, fixing a cluster panel to the vehicle in such a manner as to pass the vehicle-mounted electronic device therethrough, and fixing a panel wider than the opening in the cluster panel to the vehicle-mounted electronic device in such a manner as to place it over the cluster panel, a sub-bracket is attached to the lateral surface of the electronic device main body in such a manner that its position can be adjusted, and an attaching metal element is fastened to the sub-bracket so as to fasten the attaching metal element to the vehicle.