A transmission power control apparatus includes a transmission power control signal extracting section, transmission power control signal storage section, transmission power control determination section, and transmission power changing section. The transmission power control signal extracting section extracts a transmission power control signal from a reception signal containing a transmission power control signal. The transmission power control signal storage section sequentially stores transmission power control signals output from the transmission power control signal extracting section. The transmission power control determination section determines whether an instruction to increase/decrease transmission power based on a plurality of transmission power control signals stored in the transmission power control signal storage section is repeatedly generated. The transmission power changing section stops transmission power updating operation if the determination result from the transmission power control determination section indicates that the transmission power is repeatedly increased/decreased. A transmission power control method is also disclosed (Fig. 1).