PURPOSE: To shorten the discontinued time of a POS operation at adjustment by clearing the data stored in a memory after the sales data are stored in a back-up memory, starting the selling operation of a circumscribed terminal equipment, and adjusting and outputting the data stored in the back-up memory.

CONSTITUTION: Plural (n pieces) circumscribed terminal equipments 2(1) - 2(n) are connected to an arithmetic processor CPU 1 which performs various POS processing operations. The sales data received from the equipments 2(1) - 2(n) are stored in a memory 3 via the CPU 1. At adjustment the sales data are read out of the memory 3 through the processing of the CPU 1 and then stored in a back-up memory (e.g., floppy disk) 5. Then the sales data are read out of the memory 5 after the data stored in the memory 3 are cleared. The daily report data are printed out by a printer 4. As a result, the discontinued time of the selling operation is shortened for a POS device at adjustment.