With a network design apparatus, a network design method, and a network design processing program, a network configuration is designed for a network in which a transfer apparatus is disposed at each of a plurality of communication hubs and the communication hubs are connected via a link by a link portion apparatus in the transfer apparatus. In design of a network configuration, an optimal combination candidate of a link portion apparatus for each link for minimizing a total cost value in an overall network is calculated on the basis of a combination candidate set of link portion apparatuses. The combination candidate set of the link portion apparatuses is configured using only combination candidates with a cost-effectiveness indicating a ratio of a total capacity to a total cost value of the link portion apparatus higher than a predetermined reference.