In a piezoelectric element having a piezoelectric film sandwiched between
a lower electrode and an upper electrode, the lower electrode and/or the
upper electrode and the piezoelectric film comprise perovskite oxide and
a contact interface between the lower electrode and/or the upper
electrode and the piezoelectric film does not exist and a region where
crystals of the lower electrode and/or the upper electrode and crystals
of the piezoelectric film are mixed exists between the lower electrode
and/or the upper electrode and the piezoelectric film.