Abstract: An apparatus for cleaning escalator steps having grooved front surfaces cleans during the operation of the escalator. A brush extending across the entire width of each step is positioned under the rear edge of the tread. The bristles of the brush press against the front surface of the adjacent step when the steps are in predetermined regions of the escalator. The relative motion of the steps as they move from the horizontal to the inclined and back to the horizontal regions creates a relative vertical motion between the brush and the front surface for the cleaning of the front surface. The front surface thus is cleaned twice per revolution of the step conveyor by being moved against the brush bristles, once from top to bottom and once from bottom to top, practically across the entire height of the step.