A radio transmitter includes a signal processing circuit splitting a basic modulating signal into first and second modulating signals and outputting the first and second modulating signals. A PLL decides a fundamental wave. A VCO forms a portion of the PLL and modulates the fundamental wave decided by the PLL in accordance with a voltage of the first modulating signal outputted from the signal processing circuit. A PLL circuit forms a portion of the PLL and varies a frequency division ratio to modulate the fundamental wave decided by the PLL in accordance with the second modulating signal outputted from the signal processing circuit.