Abstract: The present invention provides an electric tool comprising a body, an operating component, an output shaft, and a stop mechanism. An arresting disc is disposed on the output shaft, and a groove is formed on the arresting disc; the stop mechanism comprises a protrusion, for example, a pin, which is operable so that the protrusion extends to insert into the groove to lock the output shaft. A stop mechanism of the present invention is easy to operate, delivers good safety performance, and has a relatively simple structure, which allows convenient production and subsequent maintenance. Further, a stop mechanism of the present invention automatically springs back to a non-stop position at which it detaches from the output shaft or the transmission gear of the transmission mechanism when the external force is lost, which prevents possible damage to the output shaft or transmission mechanism when a user starts the electric tool before releasing the stop mechanism.