Spread spectrum transmission of information is performed using chaotic signals. Direct chaotic communication systems in which information is input to chaotic signal generated directly in information transmission frequency band, are achieved by forming broadband information carrier necessary for transmission and using a chaotic dynamic system whose structure is synthesized in advance in accordance with predetermined characteristics of broadband information carrier to cause chaotic dynamic system to provide operation of forming the broadband information carrier in form of a chaotic information carrier having prescribed spectral characteristics. Modulating the chaotic information carrier is carried out by forming chaotic radio or optic chaotic pulses from chaotic information carrier, with predetermined time intervals between pulses in accordance with the transmitted information signal, and the reception and demodulation at the receiving side is carried out using a dynamic system matched, in behavior, with chaotic dynamic system of transmitting side.