A quick-release angle measuring device is disclosed. The quick-release angle measuring device is applied to a hand tool, and includes a body, an angle sensor, a controller, a monitor and a power supply. The body has a quick-release part arranged on the body and for being detachable connected to the hand tool. The angle sensor is arranged in the body for detecting an angle value of the hand tool. The controller is arranged in the body and is signally connected to the angle sensor for a user to set a factor on the angle value. The monitor is arranged on the body and is signally connected to the controller for displaying the angle value. The power supply is arranged in the body for supplying electric power to the controller, the angle sensor and the monitor.