The present invention relates to a sludge drying device, and more particularly, but by using a microwave quick drying of various sludge generated in commercial or industrial use, in particular to recycle the gas generated during the sludge drying energy for drying the sludge, with minimal pollution to use relates to the sludge drying apparatus that can more rapidly dry. According to the present invention, using the microwave is injected from the magnetron after but quickly dried various sludge generated in commercial or industrial use, in particular to remove the gas, containing the odor from the water vapor generated during the sludge drying in a condenser heat was recycled through a plasma generator, it uses as an energy source for drying the sludge can be obtained a great efficiency, while minimizing the environmental pollution an effect that can more rapidly dry. Sludge drying apparatus, a magnetron, a condenser, a thermal plasma generator