A radio channel initial transmission scheme for a mobile communication system which is capable of reducing an unnecessary interference with respect to the other radio channels as well as an unnecessary consumption of a battery of a mobile station. In the present invention, this is realized by not carrying out a transmission of the unnecessary general information during an initial period of a radio channel set up. More specifically, only the constantly necessary information among radio channel transmission signals is initially transmitted from a transmitting side of the base station and the mobile station, at a time of setting up a radio channel between the base station and the mobile station, and then the constantly necessary information and the general information other than the constantly necessary information are subsequently transmitted from the transmitting side, after a receiving side of the base station and the mobile station becomes ready to receive the radio channel properly.