A processing equipment comprising: - a processing unit having a plurality of functions; - a retaining unit retaining a device identifier capable of identifying the processing equipment; - an interface unit communicating with an operation terminal and receiving a function authentication key which is a code for setting a specific function among the plurality of functions to be enabled or disabled; and - a control unit setting the specific function to be enabled or disabled according to the function authentication key when a device identifier included in the received function authentication key coincides with the device identifier retained in the retaining unit, wherein when a signal for instructing enabling of a specific function among the plurality of functions is received from the operation terminal via the interface unit, the control unit creates a license request signal for requesting a management equipment to issue the function authentication key, and conceals the license request signal so that a content of the license request signal cannot be grasped except by the management equipment, and transmits the license request signal to the operation terminal via the interface unit, when the function authentication key issued by the management equipment is received from the operation terminal via the interface unit, the retaining unit retains the function authentication key and the control unit sets the specific function to be enabled or disabled according to the function authentication key, the processing equipment includes at least one processing unit, each of the at least one processing unit has the plurality of functions, the function authentication key includes a number of effective licenses which indicates a maximum number of the at least one processing unit capable of respectively enabling the plurality of functions, the interface unit receives a function setting signal for instructing to enable or disable the specific function to the at least one processing unit, the control unit calculates a number of necessary licenses which is a number of the at least one processing unit enabled in case of being set based on the function setting signal, and the control unit sets the specific functions of the at least one processing unit to be enabled or disabled when the number of necessary licenses is equal to or less than the number of effective licenses. - a processing unit having a plurality of functions; - a retaining unit retaining a device identifier capable of identifying the processing equipment; - an interface unit communicating with an operation terminal and receiving a function authentication key which is a code for setting a specific function among the plurality of functions to be enabled or disabled; and - a control unit setting the specific function to be enabled or disabled according to the function authentication key when a device identifier included in the received function authentication key coincides with the device identifier retained in the retaining unit, wherein when a signal for instructing enabling of a specific function among the plurality of functions is received from the operation terminal via the interface unit, the control unit creates a license request signal for requesting a management equipment to issue the function authentication key, and conceals the license request signal so that a content of the license request signal cannot be grasped except by the management equipment, and transmits the license request signal to the operation terminal via the interface unit, when the function authentication key issued by the management equipment is received from the operation terminal via the interface unit, the retaining unit retains the function authentication key and the control unit sets the specific function to be enabled or disabled according to the function authentication key, the processing equipment includes at least one processing unit, each of the at least one processing unit has the plurality of functions, the function authentication key includes a number of effective licenses which indicates a maximum number of the at least one processing unit capable of respectively enabling the plurality of functions, the interface unit receives a function setting signal for instructing to enable or disable the specific function to the at least one processing unit, the control unit calculates a number of necessary licenses which is a number of the at least one processing unit enabled in case of being set based on the function setting signal, and the control unit sets the specific functions of the at least one processing unit to be enabled or disabled when the number of necessary licenses is equal to or less than the number of effective licenses.