▎ 摘　　要

NOVELTY - The liquid ejection head has first electrodes (341) that are arranged in order from the diaphragm (33). The piezoelectric element (34) includes a piezoelectric layer (343) and a second electrode (342). A protective film (43) is provided in contact with a portion of the diaphragm and the wall. The 90% of the thickness of the diaphragm includes a first amorphous layer (330) in which a first layer and a second layer are laminated, or a second amorphous layer and a metal layer are provided. A second amorphous layer and a metal layer are laminated. A third amorphous layer and a carbon layer comprising a diamond-like carbon, a graphene and a carbon nanotube are laminated. USE - Liquid ejection head of serial type liquid ejection device. ADVANTAGE - The liquid ejection head has excellent discharge performance. DESCRIPTION OF DRAWING(S) - The drawing shows a cross-sectional view of a liquid ejection head of liquid ejection device. Diaphragm (33) Piezoelectric element (34) Protective film (43) First amorphous layer (330) First electrodes (341) Second electrode (342) Piezoelectric layer (343)