1. A teaching device for a robot comprising a flexible body holding unit capable of holding a flexible body and a drive unit that moves the flexible body holding unit in a predetermined direction to perform a fitting task of the flexible body to an object, in which teaching data is generated through teaching of the fitting task, the teaching device comprising: a reaching decision unit that decides that a front end of the flexible body reaches the object; a curvature acquiring unit that acquires information of evaluation of a degree of curvature of the flexible body when the reaching decision unit decides that the front end of the flexible body reaches the object; and a notification unit that performs notification about the teaching based on the information of evaluation acquired by the curvature acquiring unit.