A reset device for a computer system is provided. The reset device includes a hardware-reset signal generating circuit for outputting a hardware-reset signal to reset the computer system, a first switch, and a second switch having a first contact, a second contact, and a third contact. The third contact can be selectively electrically connected to the first contact to enable the hardware-reset signal generating circuit to output the hardware-reset signal when the first switch is turned on, or the second contact to output a software-reset signal to a central processing unit of the computer system when the first switch is turned on.