The utility model relates to a coffee machine boiling device which is used as a heating mechanism of a coffee machine for brewing coffee or relevant beverages. The coffee machine boiling device is improved in that an air pressure check valve and an S-shaped pipe are arranged in sequence between the water outlet end of a water tank and a section of outgoing heating pipe, and a water pump and an air escape valve are arranged in proper positions on a hot water container for storing hot boiled water and the like, which are heated to a default temperature. The coffee machine boiling device is conducive to pushing back raw water in the S-shaped pipe and temporarily closing water in the water tank when being used for heating raw water, and can apply proper pressure through the water pump to lead heated water into a container for brewing beverages again when the water is heated and led into the hot water container.