This paper presents a speed controller method based on the disturbance torque observer for high-performance speed control of the brushless DC (RLDC) motor. In case of the speed control of robot arms and tracking applications with lower stiffness, we cannot design the speed controller gain to be very large from the viewpoint of the system stability Thus, the feedforward compensation method using disturbance torque observer was proposed. This method can improve the speed characteristic without increasing the speed controller gain. The speed characteristic against disturbance torque can be improved when the bandwidth of the speed controller cannot be made large enough. Consequently, the speed control of the BLDC motor for the high-performance application become achieved.