Measuring the potential difference between the first signal between the first electrode provided elsewhere, and the second electrode used as the reference electrode, the noise processing apparatus includes a steering portion of the apparatus and the steering of the device I measures the potential difference between the second signal between the first electrode and the second electrode 3 provided on. Noise processing apparatus calculates at predetermined intervals, and the intensity of the potential difference signal and the second intensity of the potential difference between the first signal. Noise processing apparatus calculates the difference between the intensity of the potential difference signal and the second intensity of the potential difference between the first signal is calculated at predetermined intervals. In the direction in which the difference between the intensity of the potential difference signal and the second intensity of the potential difference between the first signal is eliminated, the noise processing apparatus, a potential difference signal and the second potential difference between the first signal at predetermined intervals using the calculated difference correction. Noise processing apparatus calculates a differential signal using a voltage difference signal after it is corrected at predetermined intervals, indicating a difference between the potential difference signal and the second potential difference signal in the first. Also, the noise processing apparatus outputs a differential signal.ノイズ処理装置は、装置の操舵部とは別の箇所に設けられた第1の電極と、基準電極として用いられる第2の電極との間の第1の電位差信号を測定し、装置の操舵部に設けられた第3の電極と第2の電極との間の第2の電位差信号を測定する。ノイズ処理装置は、第1の電位差信号の強度と第2の電位差信号の強度とを、所定間隔ごとに算出する。ノイズ処理装置は、所定間隔ごとに算出された第1の電位差信号の強度と第2の電位差信号の強度との差を算出する。ノイズ処理装置は、第1の電位差信号の強度と第2の電位差信号の強度との差が無くなる方向に、算出した差を用いて所定間隔ごとに第1の電位差信号や第2の電位差信号を補正する。ノイズ処理装置は、所定間隔ごとに補正された後の電位差信号を用いて、第1の電位差信号と第2の電位差信号との間の差分を示す差分信号を算出する。また、ノイズ処理装置は、差分信号を出力する。
