A transmission level control method in a wireless local loop system capable of suppressing occurrence of an unnecessarily high transmission level, comprises a step of generating a required reception level corresponding to a classification of data, a step of detecting the reception level of data at a receiver side transceiver apparatus, a step of finding a level difference between the detected reception level and the required reception level corresponding to the classification of the related received data, and a step of controlling a change of the transmission level at a transmitter side transceiver apparatus according to this level difference.