The utility model relates to a line deflection tracking device on a manual longitudinal cutting machine, which comprises a beam (8) crossing a glass roller bed and a group of incision cutter heads. The line deflection tracking device is characterized in that a group of horizontal evenly-distributed slide blocks (1) are respectively arranged on two lateral sides of the beam (8), the group of slide blocks (1) on each side are matched with a guide rail, each guide rail is provided with a horizontally-arranged rack (2), and the group of cutter heads is horizontally arranged on each rack (2). One end of each rack (2) is connected with an end portion of a round rack shaft (5), the other end of the round rack shaft (5) is provided with a rack, the rack end of each round rack shaft (5) extends into a gear box (6) to be meshed with a small gear in the gear box (6), and the small gear is driven by a hand wheel (7) outside the gear box. The line deflection tracking device has the advantages that when a glass belt deflects, all cutters of the manual longitudinal cutting machine can tack line deflection of the glass belt, thereby enabling the whole process to be time-saving, labor-saving and convenient to operate, greatly reducing adjusting time when glass deflects, and reducing reject ratio of the glass plates.