PURPOSE: To reduce the manufacturing cost of an electronic device by a method wherein a wiring board is split into a plurality of block boards and a plurality of pieces of electronic components are divided on every block board.

CONSTITUTION: In an electronic device of a structure wherein a plurality of electronic components 6 are mounted on the mounting surface of a wiring board 1, the board 1 is split into a plurality of block boards 1A and the plurality of the electronic components 6 are divided on every block board 1A. Thereby, in the case where a failure, such as disconnection or a short-circuit is generated in a wiring of the board 1, only the block board 1A in which he failure exists is separated and the block board 1A can be exchanged for the new block board 1A. Moreover, in the case where a failure is generated in some electronic component 6 mounted on the board 1, only the block board 1A mounted with the defective electronic component 6 is separated and the block board 1A can be exchanged for the new block board 1A. Accordingly, the manufacturing cost of the electronic device can be reduced.