1 : An update management system, comprising: a virtualization resource management node that manages each of virtualization resources including a physical server in which a virtual server executing a communication service is generated, and generates a new version virtual server based on an instruction to generate the new version virtual server; a service monitor that monitors the communication service executed by the virtual server; and a virtual communication function management node that instructs the virtualization resource management node to generate the new version virtual server, generates old and new correspondence data indicating correspondence between the new version virtual server and an old version virtual server, and notifies the service monitor that there is startup of the new version virtual server based on the old and new correspondence data, wherein the virtual communication function management node instructs the virtualization resource management node to perform network switching from the old version virtual server to the new version virtual server, and the virtualization resource management node executes network switching to the new version virtual server based on an instruction for the network switching.