An optical communication method includes outputting an optical data signal in which a signal amplitude of a non-data area that is an area other than a data area is made higher than a signal amplitude of the data area, to a predetermined receiver, receiving an optical input including the optical data signal with the predetermined receiver, detecting each of the signal amplitude of the non-data area and the signal amplitude of the data area of the optical input, creating a threshold for encoding the data area based on the signal amplitude of the data area, determining whether the optical data signal is received, based on the signal amplitude of the non-data area, and outputting a data signal in which the data area is encoded by using the threshold of the optical data signal, when it is determined that the optical data signal is received.