There is provided a molecular communication system capable of transmitting an information molecule in which predetermined information is encoded to a target destination with preferable control. The molecular communication system includes a molecular transmitter for transmitting an information molecule in which predetermined information is encoded, a molecular receiver for receiving the information molecule, and a molecule propagation route for connecting between the molecular transmitter and the molecular receiver. The molecule propagation route has a transmission path formed by a polymer material and a carrier molecule circulating in a predetermined direction along the transmission path. An information molecule transmitted from the molecule transmitter is mounted on the carrier molecule and the carrier molecule carries the information molecule to the molecular receiver.