An information transmission system for transmitting information from a sending apparatus to a receiving apparatus is provided. The information transmission system includes: a sending apparatus for modulating an information signal, generating a plurality of signals including an optical signal from the information signal which is modulated, and transmitting the plurality of signals via a plurality of routes; and a receiving apparatus for receiving the plurality of signals from the sending apparatus, diversity-combining the plurality of signals, and outputting the information signal, in which the plurality of signals are a plurality of optical signals or signals including a radio signal.