A base station of a wireless communication system includes: a base station side data generation portion generating a number of sets of scramble data which are different from each other while the number of sets of the scramble data is the same as or more than the number obtained by multiplying the number of the sub-channels used in said overall wireless communication system by the number of the subcarriers; a base station side storage portion which stores the scramble data; a base station side upper layer control portion which outputs both transmission data for a terminal at other end of a communication and information of sub-channels; a base station side lower layer control portion which, based on the information of the sub-channels, controls the base station side storage portion to output scramble data corresponding to the sub-channels; a base station side scramble portion which conducts a multiplication operation between the transmission data output from the base station side upper layer control portion and the scramble data output from the base station side storage portion based on a control by the base station side lower layer control portion.