The invention discloses a paddy field single side ridger ridging part gyration regulation automatic locking mechanism and belongs to agricultural machinery. A traction hanger assembly of a power input main gear box of a ridging part is provided with a support frame in a hinged mode through a swing arm A, a swing arm B and a transmission box A, a transmission box B is mounted on the support frame in a hinged mode, a power input auxiliary gear box of the ridging part is fixedly mounted on the transmission box B, a lock pin A, a lock pin B and a gliding groove are arranged outside the transmission box B, a roller is installed in the gliding groove, a transverse swing hydraulic cylinder and the traction hanger assembly are connected with the swing arm A in a hinged mode, a latch hook A and a latch hook B are respectively installed on the swing arm A and the swing arm B, a connecting rod A and a connecting rod B are respectively connected to the support frame and the latch hook A and the support frame and the latch hook B in a hinged mode, a connecting rod C and a rotary hydraulic cylinder are installed on the support frame in a hinged mode, and the two ends of the connecting rod C are respectively connected with the rotary hydraulic cylinder and the roller; the mechanism is reasonable in structure, the automatic locking is precise and reliable, the adjustment and operation are simple and convenient, and the operation efficiency is high.