A base station apparatus capable of ensuring a sufficiently large coverage of a small cell while reducing a power of downlink signals from a small-cell base station so as to be equal to or smaller than an allowable maximum power is provided. The base station apparatus of the small-cell base station comprises measurement means of measuring an interference level from a macro cell located in a periphery of the own base station and transmission-power control means of controlling a downlink transmission power based on a measurement result of the interference level from the macro cell. The transmission-power control means controls to enhance the transmission power of a downlink specific reference signal (CRS) among the downlink transmission signals of the own base station and to lower the transmission power of signals except for the downlink specific reference signal under a condition that the downlink transmission power is equal to or smaller than an allowable maximum power, when the interference level is higher than a predetermined level.