A non-virtual server and a virtual server make up the same tenant in an environment, in which virtual servers created by dividing a single physical server into a plurality of computer environments coexist with a non-virtual server that directly uses a single physical server as a computer environment without using server virtualization. A management computer is provided with virtual switch management information that shows a correlation between the virtual servers and an internal network to which a relevant virtual server connects, and physical switch management information that shows a correlation between the non-virtual server and an internal network to which the non-virtual server connects. The management computer creates a virtual server that belongs to the same tenant as a physical instance, identifies a first internal network to which the non-virtual server connects, and configures the tenant so that the relevant virtual server is connected to the first internal network.