A process is executed in which a weight value transmitted from a scale device having a placing part for placing an article, is stored in a memory as a former weight under predetermined condition, when an article code is input through a user interface, a price and a weight range corresponding to the input article code is searched from an article data file, a weight check is executed in which whether or not a weight difference between a weight value acquired by placing the article code input article on the placing part and the former weight stored in the memory falls within the searched weight range, and an article information registration process is executed only when the weight check is gone through. As for the predetermined condition may include not only before the first input of the article code in one transaction and when it is determined that the weight value is within the weight range as a result of the weight check process, but also when it is determined that the weight value received from the scale device decreases compared to the former weight.