A cash processing system , comprising: a cash processing machine capable of executing a plurality of types of cash processing; and a server to be connected to the cash processing machine via a network, wherein: the server comprises an extended function program providing section configured to provide any one of a plurality of extended function programs (P2) for executing the plurality of types of cash processing in accordance with a download request from the cash processing machine , the cash processing machine comprises: a first storage section configured to store a basic function program (P1) for executing basic processing commonly needed to execute the plurality of types of cash processing; a second storage section configured to store the extended function program (P2); and a control section configured to execute the basic function program (P1) and the extended function program (P2), wherein the control section is configured to download the extended function program (P2) corresponding to the cash processing included in a processing request from the server upon reception of the processing request designating execution of any one of the plurality of types of cash processing, to store the extended function program (P2) in the second storage section, characterized in that the second storage section is a nonvolatile memory, and in a case where the extended function program (P2) is a program corresponding to the cash processing with processing authority requested, the extended function program (P2) is deleted upon completion of the cash processing. the server comprises an extended function program providing section configured to provide any one of a plurality of extended function programs (P2) for executing the plurality of types of cash processing in accordance with a download request from the cash processing machine , the cash processing machine comprises: a first storage section configured to store a basic function program (P1) for executing basic processing commonly needed to execute the plurality of types of cash processing; a second storage section configured to store the extended function program (P2); and a control section configured to execute the basic function program (P1) and the extended function program (P2), wherein a first storage section configured to store a basic function program (P1) for executing basic processing commonly needed to execute the plurality of types of cash processing; a second storage section configured to store the extended function program (P2); and a control section configured to execute the basic function program (P1) and the extended function program (P2), wherein the control section is configured to download the extended function program (P2) corresponding to the cash processing included in a processing request from the server upon reception of the processing request designating execution of any one of the plurality of types of cash processing, to store the extended function program (P2) in the second storage section, characterized in that the second storage section is a nonvolatile memory, and in a case where the extended function program (P2) is a program corresponding to the cash processing with processing authority requested, the extended function program (P2) is deleted upon completion of the cash processing. <EOS>