A milk frothing device intended to cooperate with an automatic coffee machine, the milk frothing device including: - a mixing part comprising a mixing chamber provided with an outlet orifice, a hot water/vapor inlet orifice and a main flow conduit connecting the hot water/vapor inlet orifice to the mixing chamber, - a closure part movable relative to the mixing part between a closed position in which the closure part closes the mixing chamber and the main flow conduit and an open position in which the mixing chamber and the main flow conduit are open and accessible for cleaning, - a milk supply conduit connected to the main flow conduit, - a seal arranged at a junction area between the mixing part and the closure part and extending around the mixing chamber and the main flow conduit, and - a holding system configured to hold the closure part in the closed position, the closure part is configured to occupy an intermediate position located between the closed position and the open position and in which the closure part is located opposite the mixing chamber and the main flow conduit and is spaced apart from the mixing part, characterized in that the holding system is configured to confer on the closure part only one translational degree of freedom in a direction of translation when the closure part is displaced between the intermediate position and the closed position, the holding system being further configured to ensure a compression of the seal when the closure part is in the closed position. - a mixing part comprising a mixing chamber provided with an outlet orifice, a hot water/vapor inlet orifice and a main flow conduit connecting the hot water/vapor inlet orifice to the mixing chamber, - a closure part movable relative to the mixing part between a closed position in which the closure part closes the mixing chamber and the main flow conduit and an open position in which the mixing chamber and the main flow conduit are open and accessible for cleaning, - a milk supply conduit connected to the main flow conduit, - a seal arranged at a junction area between the mixing part and the closure part and extending around the mixing chamber and the main flow conduit, and - a holding system configured to hold the closure part in the closed position, the closure part is configured to occupy an intermediate position located between the closed position and the open position and in which the closure part is located opposite the mixing chamber and the main flow conduit and is spaced apart from the mixing part, characterized in that the holding system is configured to confer on the closure part only one translational degree of freedom in a direction of translation when the closure part is displaced between the intermediate position and the closed position, the holding system being further configured to ensure a compression of the seal when the closure part is in the closed position. the closure part is configured to occupy an intermediate position located between the closed position and the open position and in which the closure part is located opposite the mixing chamber and the main flow conduit and is spaced apart from the mixing part, characterized in that the holding system is configured to confer on the closure part only one translational degree of freedom in a direction of translation when the closure part is displaced between the intermediate position and the closed position, the holding system being further configured to ensure a compression of the seal when the closure part is in the closed position.