PURPOSE: To mount various electronic components without changing patterns of the printed wiring board by changing the printed wiring patterns between the terminal parts of an auxiliary printed wiring board.

CONSTITUTION: Electronic components 1 are connected to the first terminal parts of an auxiliary printed wiring board 3, which has said first terminal parts 31∼314 and second terminal parts 31a∼314a connected to these first terminal parts through a printed wiring board, and also the second terminal parts are connected to another printed wiring board 2 through connecting members 4. That is, in the auxiliary printed wiring board 3, the printed wiring between the first and second terminal parts, corresponding to the electronic components 1 to be mounted. Hereby, it can be mounted without changing the printed wiring of a printed wiring board on which it is mounted, so the correspondence to many kinds of electronic components becomes easy.