A vehicle control device is comprised of a plurality of functional modules that are minimum component units to contribute to fluctuations of input and output potentials and in which an input and an output of an electric power line except the one, potentials of which become equal to those on the line side and the ground side, are set to be the number of single lines or the number of single couples, respectively. The functional module is provided at one side surface with an interface surface with which a signal line and an electric power line are both connected. Each interface surface is divided into a first interface region where the signal line terminal with which a signal line is connected is arranged and a second interface region where an electric power line terminal with which the electric power line is connected is arranged. The interface surfaces of a plurality of functional modules are arranged adjacently to each other with the interface surfaces directed to the same direction, wherein the first interface regions are commonly arranged on one edge side and the second interface regions are commonly arranged on the other edge side.
