A milk emulsifying device (1, 100) comprising a hollow body (13, 130) exhibiting: - a single mixing chamber operating by Venturi effect, connected to a single steam inflow channel, to a single milk aspirating channel by Venturi effect, to a single air aspirating channel by Venturi effect provided with a check valve and to a single milk outflow channel; or - a first mixing chamber operating by Venturi effect and respectively at least a second mixing chamber by Venturi effect connected to a first steam inflow channel and respectively to at least a second steam inflow channel, to a first milk outflow channel and respectively to at least a second milk outflow channel, and to a first milk aspirating channel by Venturi effect and respectively to at least a second milk aspirating channel by Venturi effect, one between said first and second mixing chamber (14, 19) by Venturi effect being further connected to a respective air aspirating channel by Venturi effect; - a single external milk dispensing channel (30, 300) connected to said single outflow channel or to said at least a second outflow channel (16, 25); said emulsifying device (1, 100) having a first dispensing operating configuration of hot milk with a froth and a second operating dispensing configuration of hot milk without a froth and reconfigurating means (34, 35, 320) activatable for switching said emulsifying device between said first and said second configuration, characterised in that said first and second dispensing operating configurations differ in a size of the milk outflow section, the larger area milk outflow section corresponding to the second dispensing operating configuration. - a single mixing chamber operating by Venturi effect, connected to a single steam inflow channel, to a single milk aspirating channel by Venturi effect, to a single air aspirating channel by Venturi effect provided with a check valve and to a single milk outflow channel; or - a first mixing chamber operating by Venturi effect and respectively at least a second mixing chamber by Venturi effect connected to a first steam inflow channel and respectively to at least a second steam inflow channel, to a first milk outflow channel and respectively to at least a second milk outflow channel, and to a first milk aspirating channel by Venturi effect and respectively to at least a second milk aspirating channel by Venturi effect, one between said first and second mixing chamber (14, 19) by Venturi effect being further connected to a respective air aspirating channel by Venturi effect; - a single external milk dispensing channel (30, 300) connected to said single outflow channel or to said at least a second outflow channel (16, 25); said emulsifying device (1, 100) having a first dispensing operating configuration of hot milk with a froth and a second operating dispensing configuration of hot milk without a froth and reconfigurating means (34, 35, 320) activatable for switching said emulsifying device between said first and said second configuration, characterised in that said first and second dispensing operating configurations differ in a size of the milk outflow section, the larger area milk outflow section corresponding to the second dispensing operating configuration.