A dielectric thin film contains Ca, Sr, Ti, Hf, O and N, wherein among crystal grains existing in a plane field of view of 1 μm square perpendicular to a film thickness direction of the dielectric thin film, a number ratio of crystal grains having a grain size of 19 nm or more and less than 140 nm is 95% or more, among the crystal grains existing in the plane field of view, a number ratio of first crystal grains having a grain size of 65 nm or more and less than 77 nm is 20% or more, and among the crystal grains existing in the plane field of view, a number ratio of second crystal grains having a grain size of 19 nm or more and less than 54 nm is 40% or less.