PURPOSE: To realize the high speed synchronization frequency synthesizer in which synchronization is taken at a high speed even under a temperature change thereby obtaining a high frequency signal with a desired frequency quickly.

CONSTITUTION: A channel data selected and outputted from a storage means of a preset circuit 2 is used tentatively for a control voltage by a synthesizer circuit to take synchronization of a high frequency signal synchronously with a reference signal at a high speed by the high speed synchronization frequency synthesizer, to which a temperature sensor 30 outputting a voltage corresponding to a measured temperature is provided, and a channel data is selected in response to the measured temperature by the temperature sensor 30 to use it as a control voltage so as to eliminate fluctuation in the control voltage due to a change in ambient temperature thereby taking synchronization at a high speed even when the temperature is changed and outputting the high frequency signal with a desired frequency quickly.