An optical switching system is disclosed which can achieve high speed optical switching with a simple configuration. Light from a light irradiation section is irradiated into an optical transmission line made of a material having a nonlinear optical effect and disposed on the upstream side with respect to an optical switch provided for performing switching of a transmission line to cause the nonlinear optical effect to occur. Thereupon, light is emitted externally from the optical transmission line by the nonlinear optical effect between the light irradiated by the light irradiation section and light propagating in the optical transmission line. The light emitted is received by a light reception section to acquire intensity information of the light propagating in the optical transmission line. The intensity information is used as driving signal for driving the optical switch.