A mobile communication method includes an operation frequency setting method for setting an operation frequency of a radio base station including measuring by the radio base station a received power level of a common control signal transmitted by each of neighboring radio base stations, and comparing each of the measured received power levels of the common control signals with a prescribed threshold and determining an operation frequency of the radio base station from among operation frequency candidates from which a frequency of a common control signal having a received power level higher than the prescribed threshold is excluded.