An anti-theft device for a computer device, including a main body having at least one protrusion portion which protrudes from the computer device when the body is connected to the computer device, an acceleration sensor provided in the main body and configured to detect impact, a detection processing unit positioned in the main body and configured to output a signal based on the impact detected by the acceleration sensor, a first memory unit including a driver program which facilitates communication between the detection processing unit and the personal computer, a program transfer unit which temporarily installs the driver program in the computer device, a connector configured to attach the body to the computer device and facilitate electrical connection between the computer device and detection processing unit, and an indicator configured to provide indication according to the signal.