An electronic apparatus capable of saving power is provided. The electronic apparatus includes a buffer, a central processing unit (CPU), and a power supply unit. The power supply unit includes a mechanical switch circuit, a first switch circuit, and a second switch circuit. The first switch circuit is capable of being turned on by the mechanical switch circuit to receive power from a power input port and providing power to the buffer. The second switch circuit is capable of being turned on by the mechanical switch circuit to receive power from the power input port through the first switch circuit and providing power to the CPU, and the CPU being operable to generate a control signal to turn off the second switch circuit to interrupt the power provided to the CPU.