A printed wiring board includes a mounting portion on which a dual core processor including two processor cores in a single chip can be mounted, power supply lines, ground lines, and a first layered capacitor and a second layered capacitor that are independently provided for each of the processor cores, respectively. Accordingly, even when the electric potentials of the processor cores instantaneously drop, an instantaneous drop of the electric potential can be suppressed by action of the layered capacitors corresponding to the processor cores, respectively. In addition, even when the voltage of one of the processor cores varies, the variation in the voltage does not affect the other processor core, and thus malfunctioning does not occur.