To provide the intermediate frequency modulator that eliminates the need of voltage adjustment with immunity to the effect of a temperature and a secular change.

The intermediate frequency modulator 1 is provided with a coding means 11 that generates frequency transition information based on an input signal 10, a filter characteristic output means 12 that stores filter characteristics corresponding to each frequency transition information, receives the frequency transition information, reads a filter characteristic corresponding to the frequency transition information, applies filter processing to the frequency transition information based on the filter characteristic to generate a filter processing signal, and a frequency output means 13 that provides an output of a digital modulation frequency signal corresponding to the filter processing signal.