Abstract: A droplet-jetting device having high jetting ability, which includes an actuator featuring a liquid chamber and a heater and a controller. The liquid chamber has an aperture for jetting droplets of an operation liquid which the liquid chamber accommodates. The heater provides thermal energy to the operation liquid and forms bubbles for droplet-jetting. The controller controls a driving signal, which is inputted to the heater. The driving signal includes a preparatory heating pulse signal, which corresponds to a preparatory heating energy for preparatory heating of the operation liquid, and a trigger pulse signal, which corresponds to a jetting thermal energy for bubble creation and growth. A power supplied by the preparatory heating pulse signal is smaller than a power supplied by the trigger pulse signal, and a heating duration by the preparatory heating pulse signal is longer than a heating duration by the trigger pulse signal.