Disclosed are a moving distance sensing apparatus for a robot cleaner and a method therefor capable of determining a precise moving distance with respect to the robot cleaner by setting a long distance sensor and a short distance sensor having respectively different sensing method from each other on the same sensing line in the robot cleaner to sense the long distance and the short distance for the same direction, and then by determining coherency to each moving distance on the basis of information provided by the two different sensors, the moving distance sensing apparatus comprising: a long distance sensor for sensing a moving distance with respect to a long distance; a short distance sensor mounted on the same sensing line in one-to-one correspondence with the long distance sensor, for sensing a moving distance with respect to a short distance; and a micro computer for determining a moving distance error on the basis of moving distance information with respect to the same direction provided by the long distance sensor and the short distance sensor.