The invention discloses a mast correction device comprising a base (1). A pair of sliding rails (2) holding a mast are arranged on the base (1) symmetrically. The mast correction device is characterized in that a middle support (3) is movably arranged between the sliding rails (2); a two-way rod-extending hydraulic oil cylinder (4) is arranged on the middle support (3); the outer sides of the sliding rails (2) are each provided with a side edge support (5) movably; and each side edge support (5) is provided with a hydraulic oil cylinder (6).