PURPOSE: To change unit data when product information of a product is called, to call changed unit data when product information of the product is called again after another product information is called and, moreover, to easily and collectively re-changed unit data into unit data before change.

CONSTITUTION: A unit temporarily change file storing change data changing unit data of product information in accordance with a calling number is provided. When change data which corresponds when product information is called by the calling number exists in the unit temporarily change file, unit data is changed by change data. The whole contents of the unit temporarily change file are cleared by the key-input of a reset key provided in a keyboard or by the operation of adjustment job.