To efficiently carry out the decomposition of garbage.

In a garbage disposal device in which the garbage is decomposed by aerobe in stored water by supplying oxygen into the stored water W within a decomposition tank 1 into which the garbage is charged, an air-introducing opening 2, through which fresh air A is introduced into an in-tank space S above the surface of the stored water in the decomposition tank 1 and a discharge opening 3, through which internal air A' is discharged from the in-tank space S, are made opened, the stored water W within the tank is sucked from a suction opening 7 provided at the bottom of the decomposition tank 1, thereby sprinkling a portion of the sucked stored water W on the surface of the stored water within the decomposition tank from a sprinkling tool 10 through a sprinkling branch 9 from a main circulation path 8. The device is provided with a circulating pump 6 which discharges the other portion of the sucked stored water W from an agitating discharge opening 12 at the bottom of the decomposition tank into the stored water within the decomposition tank through an agitating branch 11 from the main circulation path 8.