NOVELTY - Method for preparing fats and oils, involves (a) performing activated sludge treatment of organic waste using microorganisms which have capability to produce and accumulate fats and oils, (b) co-culturing (i) first microorganisms including Aurantiochytrium, and (ii) second microorganisms which secrete enzyme that decomposes e.g. starch, (c) separating the culture into solid and liquid, (d) collecting the second sludge containing microbial cells, and (e) extracting fats and oils from the microbial cell of the microorganisms in the second sludge.    USE - The method is useful for preparing fats and oils (claimed).    ADVANTAGE - The method extracts fats and oils from surplus sludge or even in fewer environmental loads, and overcomes problem of producing organic waste water and installation. The apparatus has simple structure.    DETAILED DESCRIPTION - Method for preparing fats and oils, involves (a) performing activated sludge treatment of organic waste using microorganisms which have capability to produce and accumulate fats and oils, to obtain first sludge or processed material as nutrient source, (b) co-culturing (i) first microorganisms including Aurantiochytrium, and (ii) second microorganisms which secrete enzyme that decomposes starch and/or protein, (c) separating the culture into solid and liquid, (d) collecting the second sludge containing the microbial cells of microorganisms, and (e) extracting fats and oils from the microbial cell of the microorganisms in the second sludge. An INDEPENDENT CLAIM is included for apparatus for preparing fats and oils, which comprises (a) microorganisms having capability to produce and accumulate fats and oils, and utilized in activated sludge treatment of organic waste to obtain first sludge or processed material as nutrient source, (b) culture tank which co-cultures (i) first microorganisms including Aurantiochytrium, and (ii) second microorganisms which secrete enzyme that decomposes starch and/or protein, (c) separation tank which separates culture obtained from culture tank, into solid and liquid, and (d) extracting unit which extracts fats and oils from the isolated second sludge obtained using separation tank.