A drier for a food waste disposal system. A hollow drum has a charge port and a discharge port for food waste. An agitating screw has a rotating thread which is rotatably disposed in an inner space of the drum and agitates and crushes the food waste, and a rotating shaft around which the rotating thread is disposed. A motor is installed on a first end of the drum, and provides a rotating force to the agitating screw. A crusher has a crush plate installed on a second end of the drum and a plurality of inclined crushing blades arranged radially, and a crush plate support installed around an upper portion of the crush plate. A heater is installed on an outer surface of the drum, and when powered provides high-temperature heat for the inner space of the drum, drying the food waste.