A motor control device including an automatic adjustment device that adaptively adjusts a controller included in a motor control system based on a frequency of a vibration component superimposed on a response of the motor control system, the automatic adjustment device comprising: a vibration extraction unit configured to receive the response of the motor control system and extract the vibration component from the response of the motor control system; a notch filter unit configured to receive the vibration component extracted by the vibration extraction unit ; characterized by an encoding unit configured to receive an internal state quantity of the notch filter unit calculated by the notch filter unit ; a limiter unit configured to receive an output of the notch filter unit calculated by the notch filter unit ; an adaptive updating unit configured to receive an output of the encoding unit and an output of the limiter unit ; and a unit conversion unit configured to receive an output of the adaptive updating unit , wherein the encoding unit is configured to extract and output only sign information of the internal state quantity, and output the sign information, the limiter unit is configured to calculate and output information that limits an output amplitude of the notch filter unit , the adaptive updating unit is configured to sequentially update and output an estimated value of a notch frequency, which is a filter parameter of the notch filter unit , based on a product of the output of the encoding unit and the output of the limiter unit , the notch filter unit is configured to sequentially use the estimated value sequentially calculated and output by the adaptive updating unit as the notch frequency, the unit conversion unit is configured to convert a unit of the estimated value sequentially calculated by the adaptive updating unit into hertz and output the converted value as an estimated value, and the automatic adjustment device is configured to adaptively adjust the controller included in the motor control system by using the estimated value. a vibration extraction unit configured to receive the response of the motor control system and extract the vibration component from the response of the motor control system; a notch filter unit configured to receive the vibration component extracted by the vibration extraction unit ; characterized by an encoding unit configured to receive an internal state quantity of the notch filter unit calculated by the notch filter unit ; a limiter unit configured to receive an output of the notch filter unit calculated by the notch filter unit ; an adaptive updating unit configured to receive an output of the encoding unit and an output of the limiter unit ; and a unit conversion unit configured to receive an output of the adaptive updating unit , wherein the encoding unit is configured to extract and output only sign information of the internal state quantity, and output the sign information, the limiter unit is configured to calculate and output information that limits an output amplitude of the notch filter unit , the adaptive updating unit is configured to sequentially update and output an estimated value of a notch frequency, which is a filter parameter of the notch filter unit , based on a product of the output of the encoding unit and the output of the limiter unit , the notch filter unit is configured to sequentially use the estimated value sequentially calculated and output by the adaptive updating unit as the notch frequency, the unit conversion unit is configured to convert a unit of the estimated value sequentially calculated by the adaptive updating unit into hertz and output the converted value as an estimated value, and the automatic adjustment device is configured to adaptively adjust the controller included in the motor control system by using the estimated value. <EOS>