PURPOSE: To densify the pitches of patterns by boring holes on the rear side of the patterns on a flexible circuit board and bringing the measuring terminal of an electrical-characteristic checker into contact with the patterns.

CONSTITUTION: Patterns 2 are formed to a flexible board 1 at the intervals of pitches P1 smaller than the manufacturing limits of measuring terminals 4, 5. The measuring terminal 4 brought into contact with the pattern 2 from the pattern 2 side of the board 1 is mounted while a hole 6 is bored to the substrate 1 on the rear side of the pattern 2, and the measuring terminal 5 is brought into contact with the pattern 2. Accordingly, the terminals 4, 5 can be brought into contact with the patterns 2 from the surface and rear of the substrate 1, thus densify pitches.