This invention is to enable appropriate routing based on transition prediction of network traffic. This routing control method includes: reading out predicted utilization transition data (e.g. utilization rate, or utilized bandwidth) associated with a received connection set-up request from a predicted utilization transition data storage storing said predicted utilization transition data for each resource (e.g. links between routers, or server) in a network in future; and selecting a resource satisfying a predetermined condition based on the read predicted utilization transition data. Thus, by using said predicted utilization transition data, an appropriate resource is identified in accordance with future time transition of the resource utilization rate, for example, and thereby, appropriate routing is possible. For example, when a link that a traffic volume will increase after a predetermined time exists, it is possible to judge that such a link is not used even when there are a lot of available bandwidths now.