To make a printing ink for a pattern penetrate into even a scarf joint part approximately uniformly to other part and to bring no trouble on the pattern printed on the surface by coating the surface of a wooden base sheet prepd. by scarf-jointing through an adhesive with a sealer and printing the pattern on it.

Each scarf face being a coresponding inclined face is formed on each facing end face of a pair of wooden sheets 1 being each a three-ply plywood and then, an adhesive 3 is applied and placed between the scarf faces 2 to scarf-joint both scarf faces together by bonding with the adhesive to form a wooden base sheet 4. Thereafter, a sealer 5 is applied on the whole surface of the wooden base sheet 4 and a pattern 6 being a woodgrain pattern with an edge grain is printed on the whole surface thereon with an ink. Therefore, as the surface of the wooden base sheet 4 prepd. by scarf jointing is coated with the sealer 5, the difference in degree of penetration of the ink printed thereon from the surface between the scarf-jointed part through the adhesive 3 and other parts is decreased and light and shade are not generated.