To provide an organic waste treatment apparatus capable of decomposing organic waste into carbon dioxide and water instantaneously, having a water cleaning effect and contributing to a new organic waste treatment system.

The organic waste treatment apparatus is equipped with a charging hopper 100 for charging organic waste, a screw feeder 200 for feeding the organic waste, a feed pipe 3 and a return pipe 4 both of which circulate the mixed liquid in the organic waste treatment apparatus 1, a fine grinder 310 for finely grinding the organic waste charged in the apparatus by an impact action and a shearing action to float the ground waste in the mixed liquid, a sieving sorter 320 for sorting the organic waste ground by the fine grinder 310, a microbial decomposition treatment tank 500 for decomposing the organic waste sent in from the sieving sorter 320 into carbon dioxide and water by a microbial decomposition action and a drain device 700 for draining produced water.