The present invention relates to a recycling system and a method for recycling by means of same, in which sludge, an extraction residue of oil shale, is drawn into a light oil mixing tank and mixed thoroughly by means of light oil or an extractant to separate heavy oil, then heavy oil and the extractant/light oil are additionally recovered by means of a sludge separation apparatus, and the oil shale sludge, which is an extraction residue, is transported, after preliminary storage in an intermediate storage tank, to an evaporation apparatus for recovering light oil so as to maximally recover the extractant/light oil and the like which is the final organic material possible to be recovered, thereby allowing dry oil shale residue to be generated.