The present invention provides a wiring board giving good heat dissipation over a long period of use. The present invention also provides a method for producing board, including coating a surface of a metal substrate, which is made of an aluminium plate, with a composition containing a substance having a polysiloxane structure and inorganic particles having insulating and heat-dissipating properties, curing the composition, then bonding a copper foil to the cured composition, and partially removing the copper foil, thereby forming a wiring layer.