A base station and a scrambling code setting method of automatically setting up a scrambling code, the base station including a scrambling code setting unit for setting up a base station identifier and a provisional downlink scrambling code that is provisionally assigned; and a transmitting unit for spectrum-spreading the base station identifier by the provisional scrambling code, and for transmitting the base station identifier; wherein the scrambling code setting unit assigns a lasting downlink scrambling code based on a report concerning reception of the base station identifier.