It is an object of the present invention to provide an information input/output method that is capable of imparting different functions to dots of a dot pattern displayed on a printed matter, thereby, at the time of providing information from the dot pattern, recognizing directivity and speedily providing information and that is capable of checking an error relative to a dot layout state, and further, that is capable of enhancing security. Therefore, according to the present invention, the information input/output method is provided, and includes: defining as a block a rectangular area of a square or a rectangle, of a medium face such as a printed matter; while a straight line in a vertical direction and a horizontal direction configuring a frame of the block is defined as a standard grid line, providing a virtual reference grid point by predetermined interval on the reference grid line; laying out a reference grid point dot on a virtual reference grid point; connecting the virtual reference grid points to each other and defining a straight line parallel to the reference grid line as a grid line; defining a cross point between the grid lines as a virtual grid point; generating a dot pattern obtained by laying out one or a plurality of information dots, respectively, having a distance and a direction around the virtual grid point; reading such dot pattern as image information by optical reader means; numerically valuing the dot pattern; and reading and outputting information that corresponds to the numerically valued information from storage means.