The invention relates to a device (18) for separating out debris suspended in a liquid, for a swimming pool cleaning apparatus, said cleaning apparatus comprising: —a body (11), —at least one hydraulic circuit circulating liquid between at least one liquid inlet (15) and at least one liquid outlet (16), and through the separation housing (18) that separates out debris suspended in the liquid, —a fluid circulation pump installed in the hydraulic circuit. The device (18) for separating out debris suspended in a liquid comprises means for the centrifugal spinning of the debris suspended in the liquid and a tank for collecting said centrifugally separated debris. The separation device (18) comprises a liquid supply duct (24) opening into a filtration chamber (22) defining a substantially cylindrical volume, tangentially to a cylindrical wall (201) of said filtration chamber, said filtration chamber (22) communicating with the collecting tank (23) that collects the centrifugally separated debris.