EVALUATION METHOD AND EVALUATION DEVICE

To accurately evaluate a shape of a groove to be measured on whose surface a spiral groove is formed.SOLUTION: An evaluation method for evaluating a shape of a target groove formed on a surface of an object to be measured having a rod shaft, includes: a first positioning step for measuring a shape of a reference groove by a measuring unit to position the measuring unit at a first reference position where a first amount of deviation becomes zero between a groove bottom line and a center of a field of view of the measuring unit; a reference groove measuring step for measuring a shape of a reference groove at the first reference position; a second positioning step for measuring a rod shape of a rod shaft to position the measuring unit at a second reference position where an amount of deviation is zero between a center of a field of view and an apex position of the road shaft; a third positioning step for moving the measuring unit from the second reference position along a central axis and measuring a shape of an objective groove at a plurality of measuring positions to position the measuring unit at a third reference position where difference from the shape of the reference groove is minimized; a target groove measuring step for measuring a shape of the target groove at the third reference position; and an evaluation step for evaluating a shape of the target groove based on difference from the shape of the reference groove.SELECTED DRAWING: Figure 1 【課題】螺旋状の溝が表面に形成された測定対象の溝の形状を精度良く評価する。【解決手段】棒軸を有する測定対象の表面に形成された対象溝の形状を評価する評価方法であって、測定部により基準溝の形状を測定し、溝底線と測定部の視野中央との第１ずれ量がゼロになる第１基準位置に測定部を位置決めする第１位置決めステップ、第１基準位置で基準溝の形状を測定する基準溝測定ステップ、棒軸の軸形状を測定し、視野中央と棒軸の頂上位置とのずれ量がゼロの第２基準位置に測定部を位置決めする第２位置決めステップ、測定部を第２基準位置から中心軸に沿って移動させて、対象溝の形状を複数の測定位置において測定し、基準溝の形状との差分が最小になる第３基準位置に測定部を位置決めする第３位置決めステップ、第３基準位置で対象溝の形状を測定する対象溝測定ステップ、基準溝の形状との差分に基づき対象溝の形状を評価する評価ステップ、を備える。【選択図】図１