A wireless transmission device includes a RF power amplification section for amplifying a transmit RF signal and outputting the amplified signal to a transmission antenna, a detector section, and a control section. The RF power amplification section includes a plurality of stages of amplification, the transmit RF signal is input to an input of a first one of the plurality of stages of amplification, and an output of a last one of the plurality of stages of amplification is output to the transmission antenna. The detector section includes a plurality of detectors provided so as to correspond to the plurality of stages of amplification, each for detecting an input level of a corresponding one of the stages of amplification, and a synthesizer for synthesizing together detection outputs from the plurality of detectors. The control section controls, in a feedback control, an output level of the RF power amplification section based on an output level of the synthesizer.