The invention discloses a lunch box heated by a batteries and relates to the technical field of food heating. The lunch box comprises a box body, a heating sheet, a
metal lunch box and a
battery pack,wherein the heating sheet is arranged in the box body, the periphery of the heating sheet is tightly connected with the side wall of the box body, the
metal lunch box is detachably arranged in the box body, the lower end face of the
metal lunch box is attached to the heating sheet, the heating sheet comprises a
heat conducting sheet and PTC heating sheets, the
heat conducting sheet is provided with a plurality of PTC heating sheets, and the PTC heating sheets are treated by a common negative
electrode. The
heat conducting sheet is the negative
electrode for the PTC heating sheets, the batterypack is arranged between the heating sheet and the bottom of the box body, and the
battery pack is electrically connected with the heating sheet. The lunch box is reasonable in design, the heating piece is directly in contact with the metal lunch box container for heating, water is not needed, the
voltage is completely harmless to a
human body, the batteries are arranged in the lunch box, the lunch box is convenient to carry and use, steam is not generated in the heating process, the risk of
scalding is avoided, foods are sealed in the metal lunch box in the heating process, no smell diffuses, and no
noise is generated in the heating process.