A handle locking device and an electronic system of the invention use the rotation of a handle for push movement against a case so as to move an activation bracket to have displacement relative to a swinging bracket. Pushed by the activation bracket, the swinging bracket produces a lateral swing at one end accordingly so that a hook at the end of the swinging bracket laterally moves between a locking position and an unlocking position. Further rotation of the handle will further push against the shelf where the electronic system is mounted and bring the electronic system to move relative to the shelf and eject. A single rotational stroke of the handle is transformed into consecutive unlocking movement and ejection movement. Insertion, locking, unlocking, and ejection of the electronic system on the shelf are easily done by manual operation of the handle without the need of additional tools.