[Problem] To address the problem of conventional old wood texture or antique taste boards which lack natural looking worn effects and present an appearance of an artificial treatment applied thereto. [Solution] Unlike a conventional configuration in which the rotary shaft of a roll brush is simply and fixedly arranged parallel to the wood grains of a board to which surface treatment is applied or the painted surface where paint is applied to the wood grains, the rotary shaft may be obliquely set to any angle including a right angle, and may be rotationally driven at high speed at a given inclined angle relative to the horizontal surface of the board along a left to right direction of the roll brush. This makes different “contact strength” of a roll brush such as a metal brush obliquely applied to each right and left end of the board, thereby causing the inclined roll brush to peel off the wood grains or the painted surface where paint is applied to the wood grains with difference strengths for each end of the board. This makes it possible to implement “uzukuri” (brushing process) with different designs presented along a left to right direction of the board.