To easily produce a high frequency band signal having the wide band width while maintaining the fast frequency switching performance and the phase continuity.

A 1st normal band signal is produced by a 1st normal band signal generation circuit 50 which contains a DDS (direct digital frequency synthesizer) 20. A 2nd normal band signal generation circuit 51 containing a DDS 11 produces a 2nd normal band signal. A 1st orthogonal modulator 24 produces a 1st high frequency band signal by shifting the 1st normal band signal to a high frequency area based on the local oscillation frequency. Then a 2nd orthogonal modulator 15 produces a 2nd high frequency band signal as an output signal RF by shifting a 2nd normal band signal to a high frequency area based on the 1st high frequency band signal. In such a constitution, the output signal RF having the wide band width is easily obtained while the fast frequency switching performance and the phase continuity are maintained by both DDS 11 and 20.