PROBLEM TO BE SOLVED: To decrease the cost of a method for measuring a swinging amount of an object to be dipped in a dipping treatment. SOLUTION: In the method for measuring the swinging amount, the swinging amount of an the object 4 to be coated in an electrodeposition coating line 1 is measured. At first, an internal space A is formed by a tip part 71 and side parts 72 elongating from the tip part 71 toward the lower part, and further, a measuring member 7 at which an opening part 74 capable of releasing air present in the internal space A to the outside is formed at the side part 72 or the bottom part 73 is fitted to the object 4 to be coated. Next, as the object 4 to be coated fitted with the measuring member 7 is conveyed by a conveyer 6, the object 4 to be coated is dipped into an electrodeposition coating liquid 3 stored in an electrodeposition liquid tank 2, and electrodeposition coating is applied to the object 4 to be coated. Finally, regarding the object 4 to be coated which has been subjected to the electrodeposition coating, based on the position of the grain boundary L2 between the region subjected to the electrodeposition coating and the region not subjected to the electrodeposition coating in the internal space A of the measuring member 7, the swinging amount of the object 4 to be coated in the conveying stage is measured. COPYRIGHT: (C)2007,JPO&INPIT