A brushless motor includes a bottom base, a circuit board, a rotator, a big gear, a big driven gear, a driving gear and a lid. Positioned around a shaft base inside the bottom base are two stopping posts that form an included angle with the shaft base. A positioning plate is formed at the bottom of the driving gear, restricted to move between the two stopping posts to keep the driving gear rotated in a preset angle. And, a single injection mold can make various bottom bases with diverse rotating angles for being used in the brushless motor employed for different lamps, achieving the purpose of reducing manufacturing cost.