1. A method to make a Latin square, the method being implemented in an electric circuit and comprising the steps of: setting up a degree (n) of a Latin square (R) to be newly made; setting up a permutation of a mark (m) for the degree (n) and a selecting order in accordance with the permutation; selecting and deciding a mark (m) as one of arranging factors (Eij) at each position on a line (I) and a column (J) of the Latin square (R), a selecting decision being orderly carried out along by the line (I) or the column (J) from the first position (Kij) on the line (I) and the column (J) until the last position (Knn) on the line (I) and the column (J); and this decision being carried out on the basis of selecting order through selecting the mark (m) in order to avoid the same mark (m) to be an arranging factor (Eij) already decided at a front position (Kij) on the same line (I) and column (J).