A memory error signal detecting system including a signal extracting circuit, a flip-flop, a latch circuit, and a light sign is provided. The signal extracting circuit receives a memory error signal to output a pulse signal when the memory error signal switches from a first level to a second level. When the preset end of the flip-flop receives the pulse signal, and the maintaining time of the pulse signal is maintained for a predetermine time, the flip-flop output end is set to a high voltage level. The latch circuit determines whether to output the state of the flip-flop output according to the reset signal. The light sign operates according to the state of an output end of the latch circuit. Furthermore, a computer apparatus including the memory error signal detecting system is also provided.