Provided is a spread spectrum communication system in which the data rate can be varied through a relatively simple constitution. A slave station estimates the distance to a master station by using the I and Q signals generated by carrier demodulation, selects the code of a code length associated with the estimated distance from the previously held codes, performs spreading/despreading using the same, and performs transmission/reception. The master station performs spreading/despreading using a code having the same code length as that of the code selected by the slave station.