To prevent the male screw part of a thrust plate from being loosened off the female screw part of a shaft.

This bearing mechanism 4 of a motor 10 comprises the shaft 311 and the thrust plate 5. The thrust plate 5 is fitted to the end of the shaft 311 since the male screw part 51 of the thrust plate 5 is screwed to the female screw part 3112 formed at the lower part of the shaft 311 without using an adhesive agent. In the motor 10, the rotating direction of a rotor part 3 is counterclockwise in plan view. A left-handed screw is adopted for the male screw part 51. When an impact or vibration is applied to a motor 10 during the starting, stopping, and rotating, a force is applied to the thrust plate 5 in the direction that the male screw part 51 is screwed into the female screw part 3112. Consequently, the male screw part 51 is prevented from being loosened off the female screw part 3112.