PURPOSE: To achieve simplification of a driving circuit for a piezoelectric ink jet head without lowering the limits of printing speed.

CONSTITUTION: Electrodes on one end of each of piezoelectric elements that drive a plurality of nozzles in a piezoelectric ink jet head are made independent driving electrodes 121, 122, 123 and 124 while electrodes on the other end are connected with one another and are made a common electrode 141, and is grounded. The driving electrodes are then connected to the line of positive electric source through charging pnp bipolar transistors 41, 42, 43 and 44 while being grounded through isolating diodes 51, 52, 53 and 54 and a common discharging npn bipolar transistor 48. Charging is made selectively by the aforementioned charging pnp bipolar transistors to the capacity of the piezoelectric elements, and discharging is made by the common discharging npn bipolar transistor.