To prevent the deflection of a surface plate by providing a structure difficult to exert the reaction of a hydraulic jack through a frame, and to efficiently straighten the strain of a cast die by locally pressing a part where the cast die is required.

In a straightening equipment of a cast die to straighten the cooling strain of a cast die 1 by pressing the cast die 1 placed on an upper surface of a surface plate 12 by a hydraulic jackal 50, the surface plate 12 is supported on a base plate 11 at the prescribed height by a leg body 13, a plurality or rigid frames 20 are movably arranged irrespective of the surface plate 12, and a plurality of rigid frames 20 are provided with a lower frame body 21, a side frame body 22, and an upper frame body 23 to surround the surface plate 12 in a frame shape. A plurality of hydraulic jacks are movably arranged on the upper frame body 23 of the rigid frames in the longitudinal direction of the upper frame body 23.