Provided is an event-based image processing apparatus and method, the apparatus including a sensor which senses occurrences of a predetermined event in a plurality of image pixels and which outputs an event signal in response to the sensed occurrences, a time stamp unit which generates time stamp information by mapping a pixel corresponding to the event signals to a time at which the event signals are output from the sensor, and an optical flow generator which generates an optical flow based on the time stamp information in response to the outputting of the event signals.