PURPOSE: To carry out an inspection process of electric connection easily, quickly and exactly, by a method wherein each inner lead along the short direction rectangular to the stretching direction is made wider, as it comes near to the lower surface of the inner lead, in at least each connection part.

CONSTITUTION: A lead frame for external connection is formed which is arranged while the lower surface side of each inner lead 21 is made to face one surface side out of the surface and the back of a board main body 1 and each connection part 211 is aligned to each through 11. A solder part 3 is formed which reaches the connection part 211 of each of the inner leads 21 while each of the through holes 11 is filled with the solder part 3. At least in each of the connection parts 211 of each of the inner leads 21, the inner lead 21 along the short direction rectangular to the stretching direction of the inner leads 21 is made wider as it comes near to the lower surface of the inner lead 21. Thereby whether the electric connection of conductor part of the board main body 1 is perfect can be easily judged, and the manufacturing efficiency of a mounting board T is improved.