An internal combustion heating device of a coal pyrolyzing furnace includes a coke quenching exhaust heater and at least one set of a third gas heater and a fourth gas heater with equal structures and associated with each other; wherein the coke quenching exhaust heater comprises an internal flame path, a first air supply tube, a second air supply tube, a central annular wall and a central path, wherein an internal flame path is divided into at least one set of an internal main flame path and an internal sub flame path, the central annular wall inside the internal loop wall of the carbonizing room and at least one the internal flame path isolating wall; the internal sub flame path is divided into an upper section, a middle section and a lower section.