The invention relates to a method for producing a composite board (1) that comprises a supporting core (2) linked with a cover layer (3) covering the longitudinal face (5) of the board (1). The system consisting of the supporting core (2) and the cover layer (3) is thermoplastically interlinked by subjecting it to heat and a pressing step (12) applied on the longitudinal face (5), and then cooling it off. The inventive method is further characterized in that before the pressing step (12) is performed, the system is provided with a detachable lining (4) consisting of a temperature-resistant material that covers the longitudinal face (5) of the system, and subjecting the lined system to the pressing step (12).