Provided is a multicast distribution system which can perform a multicast distribution by selecting a communication path satisfying a communication feature required by a multicast group. A distribution source router (Rs) performs a multicast distribution to routers (R1 to R5) constituting a multicast group based on an application via a mesh virtual network connected to a plurality of routers. When the CPU load ratio and the multicast group communication feature exceed threshold values, the distribution source router updates the number of branches and the depth of the multicast tree which distributes a packet from the router and starts reconfiguration of the multicast tree. When reconfiguring the multicast tree, the distribution source router references a path feature of the mesh virtual network, selects a communication path having a sufficient path feature with a higher priority, and generates a routing table based on the multicast tree.