To provide a driving method of a piezoelectric inkjet head in which a printing speed of a line type inkjet printer can be enhanced without an image quality of forming images being decreased and also without a drive circuit being complicated, and to provide the line type inkjet printer.

The driving method sets a timing for impressing drive voltage pulses to a piezoelectric deformation region of a piezoelectric actuator so that a plurality of ink droplets ejected from a nozzle so as to form a dot in the line type inkjet printer are prevented from uniting with each other during flight until they reach the surface of a sheet of paper 18 conveyed at a constant velocity, and also so that all of the ink droplets reach arrival points 20 and 21 within an assumed circle 19 of a dot formed to the surface of the sheet of paper 18. The line type inkjet printer is equipped with a control means which carries out drive control of a drive voltage waveform outputted from a power source so as to drive the piezoelectric deformation region by the driving method.