An optical packet switching apparatus includes plural optical switches, an optical switching section that switches a path of an optical packet transmitted thereto according to the switch control signal to output the optical packet, and a control section that takes out a header portion representing a destination of the optical packet transmitted, photoelectrically converts the header to generate the switch control signal according to the destination to transmit the switch control signal to the optical switching section and controls the optical switch. The apparatus further includes a light monitor section that monitors a light quantity level of the optical packet transmitted and a light quantity level of the optical packet to be sent out, and an abnormality recognizing section that recognizes an effective timing of monitoring of the light quantity levels based on the switching control signal, and recognizes an abnormality based on the light quantity levels at the timing.