A cash handling system comprising: a cash settlement apparatus, provided in a checkout counter of a store, which is configured to perform a settlement process between a clerk and a customer, by depositing and dispensing cash; a cash accounting apparatus, provided in a back office of the store, which is configured to dispense cash to be loaded to the cash settlement apparatus, and configured to deposit cash having been collected from the cash settlement apparatus; and a cash transport cassette attachable to and detachable from the cash settlement apparatus and the cash accounting apparatus, the cash transport cassette being used for a collecting process and a loading process, the cash transport cassette receiving cash from the cash settlement apparatus and transmits the cash to the cash accounting apparatus in the collecting process, the cash transport cassette receiving cash from the cash accounting apparatus and transmitting the cash to the cash settlement apparatus in the loading process, and the cash transport cassette being configured to store cash, so as to prevent a clerk from taking out the cash therein, when the cash transport cassette is detached from the cash settlement apparatus and the cash accounting apparatus wherein, the cash settlement apparatus includes an attaching unit to which the cash transport cassette is attached, a depositing unit configured to deposit cash without using the cash transport cassette, and a dispensing unit configured to dispense cash without using the cash transport cassette, cassette ID information having been read out from a memory unit of the cash transport cassette and cassette ID information having been transmitted from the cash accounting apparatus are compared to each other by a control unit of the selected cash settlement apparatus, and if both cassette ID information do not conform to each other, an error is notified to a clerk, and when the cash transport cassette is attached to the corresponding selected cash settlement apparatus, the error is cancelled, if the amount of cash having been actually loaded, and the amount information on cash, the information having been received from the cash accounting apparatus, do not conform to each other, the error is continuously notified until the error is cancelled by a manager. a cash settlement apparatus, provided in a checkout counter of a store, which is configured to perform a settlement process between a clerk and a customer, by depositing and dispensing cash; a cash accounting apparatus, provided in a back office of the store, which is configured to dispense cash to be loaded to the cash settlement apparatus, and configured to deposit cash having been collected from the cash settlement apparatus; and a cash transport cassette attachable to and detachable from the cash settlement apparatus and the cash accounting apparatus, the cash transport cassette being used for a collecting process and a loading process, the cash transport cassette receiving cash from the cash settlement apparatus and transmits the cash to the cash accounting apparatus in the collecting process, the cash transport cassette receiving cash from the cash accounting apparatus and transmitting the cash to the cash settlement apparatus in the loading process, and the cash transport cassette being configured to store cash, so as to prevent a clerk from taking out the cash therein, when the cash transport cassette is detached from the cash settlement apparatus and the cash accounting apparatus wherein, the cash settlement apparatus includes an attaching unit to which the cash transport cassette is attached, a depositing unit configured to deposit cash without using the cash transport cassette, and a dispensing unit configured to dispense cash without using the cash transport cassette, cassette ID information having been read out from a memory unit of the cash transport cassette and cassette ID information having been transmitted from the cash accounting apparatus are compared to each other by a control unit of the selected cash settlement apparatus, and if both cassette ID information do not conform to each other, an error is notified to a clerk, and when the cash transport cassette is attached to the corresponding selected cash settlement apparatus, the error is cancelled, if the amount of cash having been actually loaded, and the amount information on cash, the information having been received from the cash accounting apparatus, do not conform to each other, the error is continuously notified until the error is cancelled by a manager.