A managing unit adds update information to an entry to be updated of a table updated prior to a change of a network configuration, and deletes the update information when the update of the table caused by the change of the network configuration is completed. A packet processing unit executes a plurality of pipeline processes using the table sequentially, and suspends executing the pipeline processes when the update information is added to any entry of the table. A reprocessing control unit stores an input packet in a reprocessing queue when the pipeline processes executed by the packet processing unit is suspended, and transfers the packet stored in the reprocessing queue to the input queue when update of the table to which the update information is added is all completed.