According to one embodiment, a printed circuit board for a real-time clock IC includes a plurality of wiring layers sequentially laminated to form one substrata and including at least one layer which forms an oscillator circuit pattern having a crystal oscillator generating a reference signal and an oscillation stabilizing portion which stabilizes and oscillates the reference signal and adjusts the oscillation frequency to a target frequency, and a power supply layer arranged in at least one of a position between the plurality of wiring layers and front and rear surfaces of the substrate, and forming a power supply circuit pattern which supplies electric power to a circuit on the substrate and removing a portion of the power supply circuit pattern which has width not smaller than width of the oscillator circuit pattern in a portion of the power supply circuit pattern which overlaps with the oscillator circuit pattern.