The invention relates to a pool filter comprising a housing, which can be supported on a ground side on the base, a longitudinal axis and a transversal axis, and a water inlet, a channel outlet and a pool outlet which are embodied in the housing wall thereof. A flow path from the water inlet to the pool outlet is embodied in the housing on the filter in the filter system and a filter device is arranged in the flow path. The invention is characterised in that a pre-filtering unit is arranged in the flow path in front of the filter device.