The present invention relates to a dehydrating and evaporation-drying apparatus for sludge treatment. More particularly, the apparatus, into which sludge is introduced between a filtering belt and a high-temperature heat-generating roller, evaporation-dried, and dehydrated, comprises a sludge supply unit, a driving unit and a sludge discharge unit. The sludge supply unit includes a hopper into which sludge is injected, and a crush roller arranged beneath the hopper to crush sludge. The driving unit is arranged in the vicinity of the sludge supply unit, and includes: a driving roller which is directly connected to a motor and which to one side of which a driving gear is coupled; a high-temperature heat-generating roller, to one side of which a driven gear is coupled such that the driven gear engages with the driving gear to rotate together with the driving gear; and a filtering belt, which covers the circumferential surfaces of the driving roller and of the high-temperature heat-generating roller, so as to deliver the sludge supplied from the sludge supply unit such that the sludge can be compression-dehydrated and evaporation-dried. The sludge discharge unit includes a plurality of scrappers elastically and tightly contacting each other along the lengthwise direction of the high-temperature heat-generating roller, such that the scrappers are separable from each other and can scrap sludge compressed onto the high-temperature heat-generating roller.