Abstract: A chaos spreading code c(n) is inputted to a spreading unit 32. Data D1 and c(n) are multiplied in the spreading unit 32. A chaos spreading code d(n) is inputted to a spreading unit 42. Data D2 and d(n) are multiplied in the spreading unit 42. The chaos spreading codes c(n) and d(n) orthogonally cross each other. Outputs of the spreading units 32 and 42 are added by an adder 35 and transmitted through a transmitting unit 36 to a transmission path 38. By making an initial value which is set in a chaos sequence generator having a construction of a digital circuit different, the chaos spreading codes which orthogonally cross can be formed. Since the chaos spreading codes c(n) and d(n) orthogonally cross, an orthogonal modulating unit having a construction of an analog circuit for amplitude-modulating carriers which orthogonally cross can be made unnecessary and the construction can be simplified.