To provide a printed circuit board where noise elimination action is obtained without increasing the number of components on the board, that is, without extending the board, and where the number of components can be reduced.

A noise countermeasure multi-layered board 3 is mounted on a printed circuit board 1. The noise countermeasure multi-layered board 3 has a plurality of connectors 4a-4b that are respectively connected to a plurality of connectors 2a-2d on the printed circuit board 1 via respective flexible cables or flat cables 5a-5d. A filter to eliminate noise on a line connected via the connector 4a is built in the noise countermeasure multi-layered board 3. Noise elimination elements are integrated on the noise countermeasure multi-layered board 3.