In a metal-based print board formed with radiators, a metal foil is affixed to a front surface of a metal plate having good thermal conductivity, an insulating adhesive layer interposed therebetween. A radiator is integrally provided on a reverse surface of the metal plate, the radiator having a plurality of thin radiating fins formed upright in a tabular shape due to having been dug out by an excavating tool. The radiating fins give the radiator a large area over which heat can be released. The thickness of a first metal plate portion formed between adjacent radiating fins is less than the original thickness of the metal plate. Heat generated by an electronic component or another component provided on a side of the front surface of the metal plate is rapidly transmitted from the reduced-thickness first metal plate portion of the metal plate to each of the radiating fins of the radiator on the reverse surface side, and efficiently released from each of the radiating fins, which have a large area over which heat is radiated.