Abstract: A PLU file stored in an RAM in an electronic cash register (ECR) is provided with a storage area for storing data concerning the number of days during which commodities remain unsold for each PLU code. A CPU provided in the ECR updates by one day all data concerning the number of days during which commodities remain unsold when the business of the day is shut up and clears data concerning the number of days during which commodities remain unsold corresponding to a PLU code inputted from a keyboard or a scanner when sales data of commodities purchased by a customer is registered. In addition, the CPU is responsive to a key operation of an operator for producing a report concerning the number of commodities on which the number of commodities counted corresponding to the number of days during which commodities remain unsold is printed and a report concerning unsold commodities on which name data of commodities which remain unsold for the designated days are printed, and the like.