An optical communication base station which receives an upstream optical signal having an upstream bit rate specific to each one of a plurality of lower order communication units from a corresponding one of the plurality of lower order communication units, and which transmits a downstream optical signal having a downstream bit rate specific to each one of the plurality of lower order communication units to a designated one of the plurality of lower order communication units, includes; a first optical signal conversion unit which changes the bit rate of the upstream optical signal and thereby converts the upstream optical signal into a fixed bit-rate inter-station optical signal; and a second optical signal conversion unit which converts the inter-station optical signal into the downstream optical signal by changing the bit rate of the inter-station optical signal according to the designated one of the plurality of lower order communication units.