A coffee machine, including a grinder, a stewing vessel, and a water supply mechanism, is disclosed. The stewing vessel is connected to the water supply mechanism and is positioned below a discharging outlet of the grinder. A filter mesh is provided in the stewing vessel, which is fixed on the casing body of the coffee machine. A bean chamber is provided in the grinder, and under the bean chamber is provided a grinding unit, the grinding unit including a bean grinding chamber in which a rotating grinding plate and a stationary grinding plate are provided. The shaft of the grinding motor is connected to the rotating grinding plate, and a removable shaft coupling is provided between the shaft of the grinding motor and the rotating grinding plate.