PURPOSE: To safely overturn a casting flask at high efficience by shifting vertically and rotatively a clamping means, which clamps a molded casting flask at vertical direction and overturning the carried casting flasks having various sizes by small-sized apparatus and full automation.

CONSTITUTION: The molded casting flask, carried to the casting flask overturning apparatus 8 by a roller conveyer, is supported at the lower face thereof as ascending an arm 19 by working of a hydraulic cylinder to an arm guide frame 27 of the clamping means 10, and further held as descending the arm 14 by working of the hydraulic cylinder 29. Next, the arm guide frame 27 is ascended by the hydraulic cylinder 47 and the casting flask is overturned and descended by rotating a hydraulic motor 41. The carried flasks having various sized are overturned in full atuomatic by the small-sized apparatus 10. Therefore, the casting flask is safely overturned without any man-labor, at high speed and efficience.