To provide a synchronization follow-up circuit by which a problem caused under low speed or high speed fading of the conventional synchronization follow-up circuit is solved; and synchronization follow-up performance can be improved regardless of traveling speed by applying a control corresponding to the traveling speed.

The synchronization follow-up circuit has: a traveling speed presumption section outputting a traveling speed presumption value by presuming the traveling speed from phase state information; an equalization control section prolonging a phase difference equalization time under a high-speed fading environment by corresponding to the traveling speed presumption value and shortening the phase difference equalization time under a low-speed fading environment and outputting the phase difference equalization time to an equalization section; and a diffusion code generation section outputting a diffusion code with the generation phase of the diffusion code controlling in sample number unit in accordance with the phase state information generated from a comparator.