A packet processing apparatus includes a plurality of queues that store received packets according to types of the received packets; and a processor coupled to the plurality of queues and configured to: collect information on packet quantity of received packets in each time slot, identify a periodicity pattern of the received packets based on the packet quantity of the received packets in each time slot, based on the identified periodicity pattern of the received packets, identify a time slot section where received packets of a predetermined type are to be outputted preferentially, and control opening and closing of each of the plurality of queues in the identified time slot section.