OPTICAL BEACON

PROBLEM TO BE SOLVED: To provide an optical beacon adaptable to a DSSS, which is capable of providing an in-vehicle device with accurate safe-driving support information.SOLUTION: There is provided an optical beacon 4 performing radio communication with an in-vehicle machine of a traveling vehicle by means of optical signals. The optical beacon 4 includes a light reception part 11 including a light receiving element for converting an up optical signal constituting uplink information to an electric signal, an optical transmission part 10 including a light emitting element for converting a down signal constituting downlink information to an optical signal, and a communication control part 7 which can execute downlink switching triggered by reception of the uplink information and generation of an uplink position being a transmission position of the uplink information. The communication control part 7 causes an uplink position Dacquired on the basis of the last frame UL2 of the uplink information comprising a plurality of frames to be included in downlink information DL2 after downlink switching.