The present invention is to provide a metal-core substrate without mounting large size terminals and connectors. Hence, the metal-core substrate can be smaller and thinner. A metal-core substrate includes a metal plate, an insulating layer formed on a surface of the metal plate and a circuit pattern formed on a surface of the insulating layer, wherein a part of said metal plate is exposed to outside of the insulating layer and is utilized as connector terminals. The metal plate has a heat sink plate to heat sink a heat-generating device mounted on the metal-core substrate and connector terminal plates disposed separately from the heat sink plate and utilized for the connector terminals. The heat-generating device and a driving part thereof each are disposed on a different surface of the metal-core substrate.