An optical packet switching apparatus includes an optical coupler for branching off a received optical packet signal, an optical switch unit for switching the route of one of the branched-off optical packet signals so as to be outputted, and an optical switch control unit for controlling the optical switch unit. The optical switch control unit includes an optical-to-electrical conversion unit for converting the other of the branched-off optical packet signals into an electrical packet signal, a serial/parallel conversion unit capacitively coupled to the optical-to-electrical conversion unit, a packet density detector for detecting the packet density of the received packet signal, and a DC offset adjustment unit for adjusting the DC offset voltage of the packet signal, inputted to the serial/parallel conversion unit, according to the packet density information detected by the packet density detector.