Radio base station apparatus 100 of the present invention monitors total transmission power which is the sum of transmission power for all mobile station terminals 200-203 connected for communication, reduces the upper limit of transmission power for the lowest prioritized mobile station terminal by a predetermined amount when the total transmission power exceeds a first threshold which is referenced to determine whether or not the transmission power has been reduced, and terminates communication with the lowest prioritized mobile station terminal when the total transmission power exceeds a second threshold which is larger than the first threshold.