A read operation control system is included in an electronic cash register for checking purposes. The actual read operation is not conducted until the operator introduces numeral data indicating the cash amount contained in a drawer case of the electronic cash register. The thus introduced numeral data is compared with accumulated data stored in a memory section of the electronic cash register, the accumulated data representing the total cash amount registered into the electronic cash register. The difference between the introduced numeral data and the accumulated data is calculated, and the calculation result is printed out onto a check list.