A user PC 20 prepares a retrieve request by storing a SNMP command and a predetermined processing execution condition into a retrieve request of a SLP and transmits and outputs the prepared retrieve request to a printer 40 and others by multicast. Receiving the retrieve request, the printer 40 obtains and executes the SNMP command stored in the retrieve request of the SLP and processes a response to the retrieve request when the execution result meets the processing execution condition. Thus, the SNMP command is executed by receiving the retrieve request of the SLP and the response to the retrieve request of the SLP is processed corresponding to the execution result, it is not necessary to separately transmit or to obtain the request process of the SLP and the retrieve request of the SNMP through the network and the execution result of the SNMP command may be reflected to the process of the SLP.