A radio base station (1), which is to be pre-blockaded, transmits a pre-blockade initiate notification to radio base stations (2A-2F) neighboring the radio base station (1). Further, the radio base station (1) reduces the transmission power thereof at a predetermined reduction rate at a initiation time of the pre-blockade. Meanwhile, each of the radio base stations (2A-2F) receives the pre-blockade initiate notification and increases the transmission power at a predetermined increase rate at the initiation time of the pre-blockade, the absolute value of predetermined increase rate being equal to that of the predetermined reduction rate at the radio base station (1).