A timing signal generation device includes a GPS receiver, an atomic oscillator, a phase comparator, a frequency abnormality determination unit, a sensor unit, and a determination unit. The GPS receiver outputs 1 PPS. The atomic oscillator 30 outputs a clock signal for synchronization with 1 PPS. The phase comparator compares 1 PPS and the clock signal in phase. The frequency abnormality determination unit determines whether or not the frequency of the clock signal is abnormal, by using a comparison result of the phase comparator, and outputs frequency abnormality information including a determination result. The sensor unit detects environment information which has an influence on the comparison result. The determination unit determines a cause of the abnormality by using the frequency abnormality information and the environment information.