A power tool includes a shaft locking assembly and an electric motor. The shaft locking assembly includes a first state where a chuck is restrained from rotating and a second state where the chuck is released to rotate. The shaft locking assembly includes multiple locking portions and an execution portion. The multiple locking portions are formed on or connected to a drive shaft or the chuck. The execution portion is optionally engaged with at least one locking portion. When the execution portion moves to a first position, the execution portion is engaged with the at least one locking portion such that the shaft locking assembly is in the first state. The electric motor includes a stop state where the first position is in the at least one locking portion when the electric motor stops.