A piezoelectric thin film resonator having a stabilized temperature characteristic of resonant frequency, a method for manufacturing the same, and a communication apparatus using the piezoelectric thin film resonator are provided. The piezoelectric thin film resonator is provided with a substrate having an opening, first and second insulation films which are provided on one surface of the substrate while covering the opening and which primarily include SiO.sub.2 and Al.sub.2O.sub.3, respectively, Al.sub.2O.sub.3 having oxygen defect and being in an amorphous state, and a piezoelectric thin film which is provided on the second insulation film and is sandwiched between electrodes and which primarily includes ZnO.