Disclosed is a microwave oven having a coffee maker installed in an electronic device chamber. A cavity door is provided in front of a cavity. The electronic device chamber in which electrical elements are installed is provided adjacent to the cavity. A casing of the coffee maker is provided in front of the electronic device chamber. A water tank is provided within the casing. A funnel is provided so that the funnel can enter and go out of the interior of the casing. A container is comprised of a jug or cup. A heater is provided in a lower portion of the casing. A water supply tube has one end connected with the water tank, body portion passing through the lower portion of the casing so as to contact with the heater, and the other end arranged at the upper portion of the funnel.