PURPOSE: To easily mount a jumper wiring by improving the efficiency of function alteration followed by parts addition by forming a pad part for mounting surface-mounted parts on a wiring pattern of a sub-printed wiring board.

CONSTITUTION: Surface-mounted parts 2 are mounted on a surface mounting printed board (PC) 1 to form a soldering part 4. On the soldering part 4 a flexible PC 10 as a PC for function alteration is mounted through soldering. Provided the surface mounting parts 2 are mounted on a portion of the printed board where the flexible PC 10 is bonded and fixed, an opening part is formed for avoiding the surface-mounted parts 2. A mounted-parts pad 15 for parts addition is formed on the flexible PC 10, and additional surface mounted parts 16 such as chip parts are mounted on the mounted parts pad 15 through soldering. Hereby, a new design of the PC 1 is ensured also for function alteration.