A brushless servo includes: a DC brushless motor having an output shaft; a reduction gearbox including a speed reduction mechanism; and a control circuit board including a number of layers of PCBs that are spaced apart from each other, and two adjacent PCBs are electrically connected to each other via a flexible circuit boards. The output shaft of the DC brushless motor is connected to the speed reduction mechanism in the reduction gearbox, and the brushless DC motor and the control circuit board are arranged side by side at one side of the reduction gearbox.