A mobile communication system of an overlay configuration includes small cells that are arranged in a macro cell, in which a base station of each small cell executes shifting to a standby state in which transmission power is turned off when a mobile terminal is not in the small cell, and measuring a quality of radio waves received from the mobile terminal that is present in the macro cell, and reporting a measurement result to a base station control device, and the base station control device executes selecting one of the small cells in which the mobile terminal is to be contained, based on the measurement results reported from the base stations of the small cells, and instructing the base station of the selected small cell to shift to a communication state in which the transmission power is turned on.