An organic waste treatment apparatus according to the present disclosure includes an acid fermenter 140, a methane fermenter 150, a thickener tank 300, and a separation membrane device 400, and includes: a first circulation line 141 in which a first circulation pump 141a is installed in a linked manner so that a part of organic waste being acid-fermented in the acid fermenter 140 is supplied to the methane fermenter 150; and a second circulation line 151 in which a second circulation pump 151a is installed in a linked manner so that a part of a anaerobic digestive fluid being methane-fermented in the methane fermenter 150 is supplied to the acid fermenter 140, in which the thickener tank 300 is installed between the methane fermenter 150 and the separation membrane device 400, supplied with concentrated circulating water from the separation membrane device 400, and supplies at least a part of the supplied concentrated circulating water to the methane fermenter 150 in an indirect injection manner, such that a
