Abstract: This invention enables exactly, regularly and simply to make every Latin square which has the optional degree and mark, so that it improves a useful and effective value of a Latin square. In this invention, a degree (n) and a mark (m) for making a Latin square (R) are set up, and the mark (m) as an arranging factor (Eij) on each position (Kij) or the Latin sqare (R) is orderly selected and decided. Then, the Latin square (R) is regularly made by selecting the mark in selecting order along by a line (I) and a column (J) for avoiding the same mark on the same line (I) and column (J) at each position (Kij).