PURPOSE: To shorten time required for an operator to operate, and besides, to sell a correct commodity by setting automatically an alternate sale group by only resetting a commodity code.

CONSTITUTION: First of all, the commodity code is set. Next, it is confirmed whether the commodity of the same commodity code exists or not, and when it exists, it is confirmed whether that commodity is the same in the classification of 'hot' and 'cold', and when it is the same, that commodity is set to be the alternate sale group. In the operation of alternate sale, when first a commodity selecting button is pushed, next, the presence of the alternate sale group is confirmed, and when it is present, the commodity whose number is next to the column number sold previous time is sold, and the operation is finished.