The device for emulsifying a milk-based beverage for coffee machines comprising, operatively associated with one another, a main steam connector (2) for connecting to the coffee machine (3), an intake tube (5) for drawing milk from a milk container (4), a mixing body (6), a steam connector (7) with a reducing hole (8) placed between said mixing body (6) and said main connector (2), a mixing element (9) and a stabilizing element (10) associated with the mixing body (6), the main steam connector (2) comprising a first safety means (11) for the safe connection thereof to said coffee machine and second safety means (12) for the limited rotation of the head of the head (13) of the main connector (2) so as to direct the emulsified beverage into a container (14).