PURPOSE: To execute safely efficiently a series of treating operations for a core including cleaning operation and oil coating operation by a method wherein a hanging frame capable of setting freely adjustably a hanging position, and an engaging arm capable of rotating are provided.

CONSTITUTION: A chain sling H1 with a hanging ring is hooked on a hook H of an overhead crane. By engaging the chain sling H1 with hanging plates 52d, 52d at both ends of a hanging fitment, the whole can be hung via the hanging fitment 52. That is, the hanging fitment 52 is moved along a hanging frame 10 by conforming it to a gravity center position of the whole including a core W. Control of a feeding mechanism 51 at that time suffices by moving the hanging fitment 52 to a calculated gravity center position after a weight of the core W and the gravity center position are provided, and the gravity center position of the whole including the core W is calculated on the basis of those data. When transfer of the hanging fitment 52 is completed, the whole is hung up, and the whole including the core W can be hung horizontally.