1. A method of post-correction of a 3D feature point-based direct teaching trajectory, which corrects a direct teaching trajectory recorded using a direct teaching device including a robot arm including at least one joint, the method comprising: a feature point extraction step of extracting shape feature points having morphological features from a recorded teaching trajectory measurement value consisting of a three-dimensional position value and a measured time value; and a trajectory calculation step of classifying a segment consisting of the shape feature points as a line or curve to calculate a teaching trajectory after correction.