To provide a garbage disposer capable of decomposing garbage at a high decomposition rate even when the composition and amount of the garbage to be charged in the garbage disposal apparatus are fluctuated.

This garbage disposer is provided with a pretreatment part 10 for storing the charged garbage and a post treatment part 11 for decomposing the garbage by a microbe. The composition of the garbage to be transferred to the post treatment part can be stabilized by storing in the pretreatment part the garbage of an amount enough to be treated in several operations. New garbage is not charged in the post treatment part until the garbage charged in the post treatment part at the previous time is decomposed.