The authors propose a suppression control method for torque vibration of brushless DC motors utilizing feedforward compensation control and a generation method of compensation signals for the feedforward control by the repetitive control system with the Fourier transform utilizing a vibration signal acquired by an acceleration sensor attached to the motor frame, and in order to realize online generation of the feedforward compensation signals to reduce the vibration. An auto-tuning method of the repetitive control parameters is also presented. In this paper, an experimental system to detect and reduce the motor torque vibration is constructed, and the effectiveness of the proposed method is confirmed by experimental results.