To improve the yield of a vibrator by measuring the thickness or oscillation frequency of the plural vibration parts of a diaphragm in a large plate shape, covering the specified vibration part of the diaphragm with first resist and etching the non-covered part of the first resist thereafter.

By directly measuring the thickness of the plural vibration parts 7 of the diaphragm 22 in the large plate shape or measuring the frequency of the plural vibration parts 7 and converting it to the thickness, the thickness distribution of the vibration parts 7 of the diaphragm 22 in the large plate shape is measured, the thickness of the respective vibration parts 7 is ranked and a part for thinning the thickness of the vibration parts 7 of the diaphragm 22 in the large plate shape by etching is specified. Thereafter, resist is applied to the entire diaphragm 22 in the large plate shape, the part for thinning the thickness of the diaphragm 7 obtained by ranking is exposed and developed and the resist is removed. Then, the vibration parts 7 is thinned by etching. Thus, the thickness dispersion of the vibration parts 7 of the diaphragm 22 in the large plate shape is made small and as a result, defects by the frequency deviation of a vibrator are suppressed.