Problems to be solved: The present invention provides a metal-core-board reinforcing structure which can simultaneously satisfy various requirements such as miniaturization, weight reduction, space-saving, heat radiation and provision of mechanically reinforced metal core board. Means to solve the Problems: The metal-core-board reinforcing structure according to the present invention has a metal core board 1 having a metal core and a resin plate 2 having substantially the same extent as that of the metal core board 1 and being fixedly attached to the metal core board 1 substantially parallel to one side of the metal core board 1 and spaced apart therefrom by a predetermined distance.