To provide a method and an apparatus for treating an organic waste capable of suppressing blocking of a pressure regulating valve caused by thermal solubilizing sludge, and enabling to perform stably a continuous type thermal solubilization processing.

The treating apparatus A includes: a receiving storage tank 1 for storing the organic waste W1; a digesting tank 2 for anaerobic digestion treatment; a dehydrating apparatus 7 for performing a dehydrating treatment of the digested sludge; and a thermal solubilization reactor 3 which continuously feeds the organic waste fed continuously from the digestion tank 2 or a digested sludge storing tank 12 by regulating the pressure by the pressure regulating valve 3A provided on the downstream side, performs the thermal solubilization treatment, and returns the thermal solubilized sludge M to the receiving storage tank 1. In a flow path S, a small solid substance passing means 8 which among the solid substance of the organic waste, only the small substance with a size less than the maximum distance between the valve body and a valve seat when the pressure regulating valve 3A has the maximum opening, is made to flow to the downstream side, is provided. The small substance passing means 8 is constituted of for example, a grinding pump 11, a strainer 9 and a screen 10.