In a system having physical machine resources and network component resources, a resource management technique is provided that is effective for deploying virtual machines utilizing these resources. A surplus policy regarding surplus resources is prepared as a parameter adjustable by the system administrator. A placement plan generating program at a VM placement plan generating server generates placement plans for virtual machines in response to alteration of the surplus policy. Then, a placement plan verification program at the VM placement plan generating server validates whether each of the created placement plans complies with the altered surplus policy. This validation is performed by simulating the amounts of utilization of both physical machine resources and network component resources. The VM placement plan generating server presents the placement plans that passed this validation, as those causing no problem in performance, to the system administrator through the use of an administrator terminal.