Reducing cutter head for rectangular pipe jacking machine

The utility model relates to a reducing cutter head for a rectangular pipe jacking machine. The reducing cutter head comprises a track plate and a plurality of cutter head assemblies, a plurality of rails penetrating through a rail plate body are arranged on the rail plate in a staggered mode, and a plurality of first fixing holes are formed in the edge of each rail at intervals. The cutter head assembly comprises a cutter head, a rotating shaft, an upper connecting plate and a lower connecting plate; the cutter head is fixedly arranged at the upper end of the rotating shaft; openings are formed in the middle parts of the upper connecting plate and the lower connecting plate; a ball bearing is fixedly arranged at the opening; a plurality of second fixing holes are formed in the edges of the upper connecting plate and the lower connecting plate; the upper connecting plate and the lower connecting plate are respectively arranged on the upper surface and the lower surface of the track plate; a plurality of bolts