The utility model discloses a three-supporting motor, which comprises a motor main body component, a reduction gearbox component and a PCB component (24), wherein fillers (10) are filled in gaps between a reduction gearbox body (2) of the reduction gearbox component and a worm end supporting hole (23) of the motor main body component as well as between the reduction gearbox body (2) of the reduction gearbox component and a worm end bearing (11) of the motor main body component; and a sealing ring (12) is arranged at the tail end of the worm end supporting hole (23). In the utility model, worm end supporting parts of an armature shaft in a three-supporting statically indeterminate shaft are designed into floating-structure supporting components (including the fillers, the worm end bearing and the sealing ring), so as to firstly convert the three-supporting statically indeterminate shaft into a two-supporting statically determinate one, and then the floating-structure supporting components are rapidly and permanently solidified and fixed via the fillers (instantaneous adhesive) to restore to the three-supporting structure. Therefore, the three-supporting statically indeterminate shaft is prevented from looseness after being mounted, and the normal workload of the armature shaft is improved.