PURPOSE: To prevent an imposture practice and to allow the customer to calculate the price by providing a computer system receiving data transferred from a data read means and a weight measurement means with respect to each purchased article, comparing the data and storing the data.

CONSTITUTION: The customer passes purchased articles on a scanner 16 one after another and allows a computer to confirm information of the articles such as weight, price and name of the articles. The total weight of the purchased articles put in a reception package 12 is calculated by a scale 14 under the package 12 and compared with the total registered weight of the purchased articles in the computer and an alarm is raised when they are in excess of a prescribed enable range. The customer brings the package 12 to a cashier after the weight is summed and the final weight is measured. Thus, it is warranted that nothing is added to the package after the weight measurement. Furthermore, by using article codes together with the name of the articles and the weight, the purchased articles at a low price after scanning are not replaced with expensive articles by an imposture practice.