A self-cleaning milk foaming device includes a mixing unit, a steam jet unit and a control unit. The mixing unit has a mixing chamber, and a milk inlet passage, a cleaner inlet passage and a foaming gas inlet passage communicated with the mixing chamber. The mixing chamber has a milk outlet nozzle, an upstream section, and a downstream section disposed between the upstream section and the milk outlet nozzle. The milk inlet passage is situated between the cleaner inlet passage and the milk outlet nozzle. The foaming gas inlet passage is disposed upstream of the milk inlet passage. The steam jet unit is for supplying steam into the mixing chamber. The control unit is for controlling the cleaner to flow or to stop flowing into the cleaner inlet passage.
