Packets input from input HWs #0 to #3 to a packet switch device are buried in time slots A through D. The packet switch device alternately switches the input packets in units of time slots, and inputs the packets to two 4×4 switches. The 4×4 switches make normal switching, and distribute the packets to respective output ports. Then, the packets output from the two 4×4 switches after being switched are alternately multiplexed, and output to output HWs #0 through #3. By making switching in units of packets as described above, a process overhead is prevented from being increased, and also expansion can be easily made. Besides, hardware scale can be made small.