Method and device for the manufacture of corrugated material, at least one first plane sheet (19; 20) and one second sheet (16) of plastic material arranged in wave shape being brought together for adhesion to each other and the wave-shaped sheet (16) running over core bars (17, 18). A portion of at least one sheet is heated at abutment against the core bars (17, 18) and the first sheet (19; 20) is brought to abutment against the second sheet (16) for welding the sheets (16; 19, 20) together. First members are arranged for feeding at least the first plane sheet and the second sheet of plastic material running over core bars (17, 18) and second members are arranged for bringing together and adhering the sheets. Heating members (28) are arranged for transferring heat to a portion of at least one sheet (16; 19, 20) abutting against the core bars and including plastic material. Furthermore, guide members (17, 18; 21; 22) are arranged for bringing together the first and the second sheet in an abutment portion and for welding in the portion heated by the heating members (28).