An automatic toner supply device for automatically supplying toner into a toner cartridge of a laser printer or a copy machine, the automatic toner supply device comprising: a toner storage container for storing toner to be refilled; an outer container for accommodating the toner storage container; a toner supply unit for supplying the toner stored in the toner storage container into a toner cartridge; and a toner supply hose connected to a lower portion of the toner storage container to transfer the toner into the toner cartridge by the toner supply unit, a control part for receiving a signal transmitted from the toner cartridge, the control part comprising a controller controlling the toner supply unit - characterized in that the toner supply unit comprises: a balloon that is expanded or contracted when air is supplied into or discharged from the inside thereof to push the toner in the lower portion of the toner storage container toward the cartridge or supplement the toner in the lower portion of the toner storage container with additional toner from an upper portion of the toner storage container; an air pump for supplying air into the balloon; an air pipe for connecting the balloon to the air pump; wherein when shortage of the toner is detected by a low sensor provided in the toner cartridge the controller automatically repeatedly expands and contracts the balloon by a number that are initially input in the controller to supply the toner into the toner cartridge. a toner storage container for storing toner to be refilled; an outer container for accommodating the toner storage container; a toner supply unit for supplying the toner stored in the toner storage container into a toner cartridge; and a toner supply hose connected to a lower portion of the toner storage container to transfer the toner into the toner cartridge by the toner supply unit, a control part for receiving a signal transmitted from the toner cartridge, the control part comprising a controller controlling the toner supply unit - characterized in that the toner supply unit comprises: a balloon that is expanded or contracted when air is supplied into or discharged from the inside thereof to push the toner in the lower portion of the toner storage container toward the cartridge or supplement the toner in the lower portion of the toner storage container with additional toner from an upper portion of the toner storage container; an air pump for supplying air into the balloon; an air pipe for connecting the balloon to the air pump; wherein when shortage of the toner is detected by a low sensor provided in the toner cartridge the controller automatically repeatedly expands and contracts the balloon by a number that are initially input in the controller to supply the toner into the toner cartridge. a balloon that is expanded or contracted when air is supplied into or discharged from the inside thereof to push the toner in the lower portion of the toner storage container toward the cartridge or supplement the toner in the lower portion of the toner storage container with additional toner from an upper portion of the toner storage container; an air pump for supplying air into the balloon; an air pipe for connecting the balloon to the air pump; wherein when shortage of the toner is detected by a low sensor provided in the toner cartridge the controller automatically repeatedly expands and contracts the balloon by a number that are initially input in the controller to supply the toner into the toner cartridge.