In an ink-jet head as a liquid-droplet jetting apparatus, a manifold channel which supplies an ink to pressure chambers has a first area communicating with the pressure chambers and a second area communicating with a dummy nozzle formed therein, with the first and second areas sandwiching a projection therebetween. Air exists at an upper portion of the second area, and the air is in contact with the ink in the manifold channel. When a pressure is applied to the ink in the pressure chambers by a piezoelectric actuator so as to jet the ink from nozzles, a pressure wave is generated in the pressure chambers and is propagated to the manifold channel. The pressure wave propagated to the manifold channel is attenuated in the second area by the air which is in contact with the ink in the manifold channel.