A piezoelectric thin film element includes a bottom electrode, a piezoelectric layer, and a top electrode on a substrate. The piezoelectric layer includes, as a main phase, a perovskite-type oxide. The bottom electrode has a surface roughness of not more than 0.86 nm in arithmetic mean roughness Ra or not more than 1.1 nm in root mean square roughness Rms. The bottom electrode has a (111) preferential orientation in a direction perpendicular to the substrate.