To solve a problem that a first piezoelectric element pillar particularly is liable to fall down when high density is attempted when a plurality of piezoelectric element pillars are formed by applying channel processing to a piezoelectric member.

The piezoelectric member 1 joined to a base member 8 has a region 1C where internal electrodes 3A and 3B are not present, and the channel processing is started from a region 1C where the internal electrodes 3A and 3B are not present to form a first channel 10a, and while a blade 9 is moved in one direction, the channel 10 is successively processed by an equal pitch to form a plurality of the piezoelectric element pillars 11 by the equal pitch.