CUTTING LINE MAKING DEVICE FOR PLATE-SHAPED OBJECT, CUTTING LINE MAKING METHOD FOR PLATE-SHAPED OBJECT, PRODUCING DEVICE FOR GLASS PLATE AND PRODUCING METHOD FOR GLASS PLATE

PURPOSE: A cutting line processing device of a flat panel is provided to process the cutting line of the flat panel with high dimensional degree of precision even in case a diameter of a roller is changed by changing traveling speed of the cutting line processing means. CONSTITUTION: A cutting line processing device of a flat panel (10) comprises: a quantity detecting means of returned flat panel (100); a cutting line processing means (20); a driving means; a cutting means (52); a measuring means (104A,104B); and a controlling means. The quantity detecting means of returned flat panel comprises: a roller (102); a signal generating means; and calculating means. The roller is contacted with the returned flat panel and rotated. The signal generating means generates a signal according to a quantity of a rotation of the roller. The calculating means computes the quantity of the returned flat panel based on the signal. The driving means operates the cutting line processing means thereby processing the cutting line on surface of the flat panel. The cutting means cuts the flat panel according to the cutting line. The measuring means measures a length of a space between two cutting lines which are faced with the flat panel which is cutting line processed; and length of returning direction of the flat panel which is cut. The controlling means changes the traveling speed of the cutting line processing means based on the changed amount about the standard value or the length of the space between two cutting lines which is measured.