A virtual network monitoring apparatus includes an acquisition unit configured to acquire first network information, the first network information being network information possessed by a virtual machine control unit functioning as an orchestrator, and second network information, the second network information being network information possessed by a virtual machine generated by the virtual machine control unit among network information on a virtual network to which the virtual machine is connected, and a generation unit configured to generate a traffic filter indicating a filter for traffic flowing through the virtual network on the basis of the first network information and the second network information.