The invention discloses a multi-module variable-frequency heating device which comprises a heating disc, a heat insulation plate and a
stroke guide rod. A through hole penetrating through the heatingdisc body is formed in the middle of the heating disc, at least one groove is formed in the upper surface of the heating disc,
electric heating wires are packaged in the grooves, the electric heatingwires are electrified and heated through binding posts, and each
electric heating wire corresponds to two binding posts; a
binding post installation hole penetrating through the heat insulation plateis formed in the heat insulation plate, a through hole is formed in the middle of the heat insulation plate, and a counter bore with the
diameter larger than that of the through hole is formed above the through hole of the heat insulation plate. The end, provided with the external threads, of the
stroke guide rod can penetrate through the through hole in the heating disc and a counter bore in theheat insulation plate in an up-down moving mode, and the through hole extends out of the heat insulation plate; the end, provided with the internal threads, of the
stroke guide rod is sleeved with a spring, the bottom of the spring abuts against the bottom of the counter bore, the upper portion of the spring is sleeved with a
gasket, the screw is installed on the internal threads of the stroke guide rod in a threaded mode to press the
gasket on the spring, and the
gasket is higher than the heating piece under the pressure-free condition. The device is simple in structure and convenient to use.