I-shaped steel sawing device capable of automatically adjusting length

The utility model relates to an H-shaped steel sawing device capable of automatically adjusting length, which comprises a bending machine, a cutting mechanism and an adjustable fixed-length mechanism which are sequentially arranged in the longitudinal direction and are distributed in the longitudinal direction, and the adjustable fixed-length mechanism comprises a fixed-length mechanism part rack, a fixed-length mechanism part supporting roller and a fixed-length structure part comparison structure. The fixed-length structure part comparison structure comprises a blocking plate and a blocking plate lifting air cylinder, the blocking plate can move between the upper side and the lower side of the horizontal plane of the second fixed-length structure part under the driving action of the blocking plate lifting air cylinder, and the blocking plate is aligned to a gap between adjacent fixed-length mechanism part supporting rollers; the distance between the plane where each blocking plate is located and the cutting