A printed wiring board device used for electronic equipment, such as the information equipment, etc. A printed wiring board (10) has a power source layer (11) and a ground layer (12) and is mounted with active elements (3 and 4), such as digital ICs, etc. A first capacitor (1) which conductively couples the layers (11 and 12) with each other at a high frequency is provided in the peripheral section of one end side or the other end side of the section of the board (10) where the layers (11 and 12) are faced to each other. Second capacitors (2) which respectively supply transient currents to the active elements (3 and 4) are provided between the power supply pins (3V and 4V) of the elements (3 and 4) and the ground layer (12) near the elements (3 and 4). Therefore, the electromagnetic radiation caused by the power source layer (11) and the ground layer (12) of the printed wiring board (10) can be suppressed easily and remarkably.