PURPOSE: To detect front and rear and directionality by providing a semicircular recess groove at a center and a cutout of an opposite edge at a rear side of a mounting component of a square shape.

CONSTITUTION: A mounting component 1 is formed at its outer frame of an insulating material, and a central position to be laterally symmetrical of a rear surface 2 is formed in a structure having a recess groove 3 passed at both lateral ends. After the component 1 is detected at its front side and directionality, it is conveyed to a predetermined position on a board 22 and mounted. In a structure in which patterns 24a, 24b for connecting are provided so as to bridge a pattern 23, resist 26 is provided on the pattern 23 before the component 1 is mounted, and a silk 27 is placed so as to cover the resist 26. In this case, the silk 27 is engaged with the groove 3 to prevent solder 25 from floating at one side. Thus, the generation of a tomb stone phenomenon, solder ball, etc., can be prevented.