Coating thickness inspection method and coating thickness inspection device

A coating thickness inspection device for inspecting the thickness of a coating section of a rectangular wire, the rectangular wire consisting of a rectangular conductor having a narrow and long shape, cross-section of which has a rectangular shape, and the coating section coating the rectangular conductor, comprising:

• an external shape measurement part for measuring an external shape of the rectangular wire across a lengthwise direction of the rectangular wire;
• a position calculation part for determining the position of the rectangular conductor within the rectangular wire across the lengthwise direction of the rectangular wire;
• and
• a determination part for determining whether the thickness across a peripheral direction of the coating section as calculated on the basis of the results obtained by the external shape measurement part and the position calculation part and the size of the rectangular conductor satisfies a standard thickness across the lengthwise direction.