A synchronization error occurs when a DTV signal is distorted on a transmission path and this deteriorates demodulation capability. The digital demodulation device and the synchronization detecting method of the invention can correct the synchronization position when determining that a synchronization error has occurred. A controller receives a center tap coefficient, for example, from a waveform equalizer and compares the coefficient with a given center tap coefficient threshold. If the coefficient is smaller than the threshold, the controller determines that a synchronization detector has made a synchronization error and outputs a control signal. The synchronization detector receiving the control signal re-detects a sync signal included in a received signal, to detect a new correct sync signal and thus correct the synchronization error.