PURPOSE: To provide a method of punching thick boards such as plywood and solid boards for construction and furniture uses wherein punching is made practicable, producing no gaps at the surface section even in a thick board that cannot be cut at a time by a knife by carving grooves from the back by a rooter.

CONSTITUTION: Grooves 4 are carved in a thick and hard board 1 of 3 mm thick or more such as laminated plywood and solid boards, carving being carried out from the back 2 of the board and along a desired pattern by means of a rooter 3. Then, remaining sections 7 having a thickness of 1 mm or less between the bottom 5 of the grooves and the surface 6 are cut at a time by means of a knife 8 so as to separate the thick board 1 into a piece 9 punched and pieces 10. Punching may also be carried out by providing streaks of about 1 mm depth beforehand from the surface 6 and along the desired pattern by means of the knife 8, carving the grooves 4 from the back 2 by use of the rooter 3, and punching.