To provide an underwater decomposition type garbage disposal equipment capable of stably performing a decomposition treatment by microorganisms by maintaining a decomposing liquid at an optimum set temperature.

The underwater decomposition type garbage disposal equipment is constituted to introduce garbage into a decomposing tank 2 after crushing the garbage with a garbage feeder 1, to be decomposed by the microorganisms of a decomposing liquid stored in the tank 2, to draw a part of the decomposed liquid into a drying equipment 6, and to discharge the dried matter thereof after subjecting the decomposed liquid to drying treatment, in which a hot air pipe 62 provided with a blower 63 and communicated with the upper space of the tank 2 is coupled to the drying equipment 6 and the tank 2 is provided with a liquid temperature detector 22 for detecting the temperature of the decomposed liquid and is so arranged as to control the operation of the blower 63 with a controller in accordance with the result of the detection with the detector 22. The tank 2 is provided with an auxiliary heater 21 for heating the decomposed liquid and the controller is so constituted as to control the operation of the auxiliary heater 21 in accordance with the result of the detection with the detector 22.