An event signal processing method and an event-based sensor performing the event signal processing method are provided. The event signal processing method includes receiving an activation signal to indicate sensing of an event from a sensor array, increasing the cumulative event number of a sensing area corresponding to the activation signal among sensing areas of the sensor array, reducing the cumulative event number of each of the sensing areas based on a parameter; and determining, as a flickering area, a sensing area among the sensing areas, of which the cumulative event number exceeds a threshold.