Based on the orientation of the sensor unit respectively, assuming a temporary link of linear dimensions equal to the sensor dimension between the between the sensor units each endoscope shape detecting device, temporarily in the sensor units each a sensor temporary position detector for detecting the position, on the basis of the temporary position of the sensor units each performing curve interpolation with temporary arc between the provisional position of the sensor unit of each provisional curve the insertion portion I provided, and a provisional curve shape detection unit for detecting a shape. The endoscope shape detecting apparatus includes a sensor positioned on the basis of the absolute value of the difference between the sensor dimension between the arc length of the temporary Each circular arc and correct final position from the temporary position to the position of the sensor units each I provided, and a final curve shape detection unit to curve interpolation in the final arc between a correction unit, the final position of the sensor unit of each, to detect the final curve shape of the insertion portion.内視鏡形状検出装置は、それぞれのセンサユニットの姿勢に基づいて、それぞれの前記センサユニットの間を寸法がセンサ間寸法に等しい直線状の仮リンクと仮定して、それぞれの前記センサユニットの仮位置を検出するセンサ仮位置検出部と、それぞれの前記センサユニットの前記仮位置に基づいて、それぞれの前記センサユニットの前記仮位置の間を仮円弧で曲線補間を行い、前記挿入部の仮曲線形状を検出する仮曲線形状検出部と、を備える。内視鏡形状検出装置は、それぞれの前記仮円弧の弧長と前記センサ間寸法との差の絶対値に基づいて、それぞれの前記センサユニットの位置を前記仮位置から最終位置まで修正するセンサ位置修正部と、それぞれの前記センサユニットの前記最終位置の間を最終円弧で曲線補間し、前記挿入部の最終曲線形状を検出する最終曲線形状検出部と、を備える。
