A method for driving a liquid drop ejector (1) equipped with a piezoelectric actuator (7) including a piezoelectric ceramic layer (6) having a size covering a plurality of pressurizing chambers (2). An arbitrary piezoelectric deformation region (8) of the liquid drop ejector (1) is deflected in one thickness direction and the opposite direction, respectively, by applying a driving voltage waveform including a first voltage (−VL) and an equivalent second voltage (+VL) of the opposite polarity in order to vary the volume of the pressurizing chambers (2) of a corresponding liquid drop ejecting portion (4), and a liquid drop is ejected through a communicating nozzle (3). Since gradual creep deformation of the inactive region (16) of the piezoelectric ceramic layer (6) is prevented, the ink drop ejection performance is maintained at a good level over a long term.