GEOMETRIC QUANTITY MEASURING APPARATUS AND GEOMETRIC QUANTITY MEASURING METHOD

PROBLEM TO BE SOLVED: To provide a geometric quantity measuring apparatus capable of measuring geometric quantity by using a relatively small reference gauge.SOLUTION: A geometric quantity measuring apparatus 50 for measuring straightness of a workpiece W comprises three distance sensors 9A, 9B and 9C of a first group, which are arranged on a predetermined straight line with a first distance L1 from each other, a sensor head 9 having three distance sensors 9a, 9b and 9c of a second group, which are arranged on the predetermined straight line with a second distance D1 from each other shorter than the first distance L1, and an actuator 8 for table movement which relatively moves the sensor head 9 to the workpiece W along the predetermined straight line. 【課題】比較的小さい基準ゲージを用いて幾何学量を測定できる幾何学量測定装置を提供すること。【解決手段】ワークＷの真直度を測定する幾何学量測定装置５０は、所定直線上に第１距離Ｌ１ずつ隔てて配置される３つの第１群距離センサ９Ａ、９Ｂ、９Ｃと、その所定直線上に第１距離Ｌ１より小さい第２距離Ｄ１ずつ隔てて配置される３つの第２群距離センサ９ａ、９ｂ、９ｃとを有するセンサヘッド９と、ワークＷに対してセンサヘッド９をその所定直線に沿って相対移動させるテーブル移動用アクチュエータ８と、を含む。【選択図】図２