To provide a bamboo material developing and processing method which can deform and process a cylindrical bamboo material into a good flat plate-like bamboo material with no damage, and a bamboo material developing and processing jig used for this bamboo material developing and processing method.

There is provided the bamboo material developing and processing method for compressing a cylindrical bamboo material W1 circumferentially in advance and then develops it into a flat plate-like shape. In addition, there is provided the bamboo material developing and processing method for developing the cylindrical bamboo material W1 into the flat plate-like shape while it is compressed in the peripheral direction. In addition, a bamboo material developing and processing jig 100 includes a cutting/tearing part 20 having a tearing blade which cuts and tears lengthwise the cylindrical bamboo material W1 and a developing part 30 exhibiting a cross-sectional shape in which the degree of spreading of a circular arc becomes gradually larger in the moving direction of the bamboo material W1 and gradually develops the cylindrical bamboo material lengthwise cut and torn by the tearing blade into the flat plate-like shape.