A mobile optical communication system for transmitting data to a mobile unit is described, wherein a leaky optical fiber (916) transmits an optical signal modulated in accordance with data with leakage thereof out of the surface and is deployed along a movement route of the mobile unit (911), wherein the mobile unit comprises: a light receiving unit (912) that is deployed almost facing the leaky optical fiber (916) and receives an optical signal leaked out of the leaky optical fiber; and a demodulator (913) that demodulates an optical signal received by the light receiving unit, thereby capturing data; wherein the data is optically transmitted to the mobile unit through the leaky optical fiber.
