Pinion-equipped motor and gear mechanism provided with pinion-equipped motor

According to the present invention, it is possible to provide a pinion-equipped motor having a shaft provided with a pinion having a complete tooth-shaped portion functioning as a gear, in which the complete tooth-shaped portion of the pinion can be shifted toward the base end side of the shaft so as to shorten the length of the pinion in the axial direction. A pinion-equipped motor has a shaft provided with a pinion at the tip thereof, in which the pinion has: a base part attached to the shaft; a complete tooth-shaped part having an outer diameter less than or equal to the outer diameter of the shaft and functioning as a gear; and an incomplete tooth-shaped part provided between the base part and the complete tooth-shaped part, the length of the incomplete tooth-shaped part in the axial direction of the shaft being equal to or less than the length of the complete tooth-shaped part in the axial direction, and the incomplete tooth-shaped part not functioning as a gear. 可提供一种带小齿轮的马达，其具有设置有小齿轮的轴，该小齿轮具有作为齿轮发挥功能的完