An ink jet head for a printer wherein an ink drop is ejected from a nozzle to fly and land on the recording paper to form an image. The ink jet head includes the nozzle for ejecting ink, an ink channel that communicates with the nozzle, a pair of oscillating plates that are opposing to each other on walls of the ink channel, a pair of electrodes disposed in contact with the oscillating plates, an ink chamber for holding the ink, and an inlet for supplying the ink from the ink chamber to the ink channel. A gap between the electrodes is filled with the ink having a relative dielectric constant higher than air. A voltage is applied between the electrodes.