Method of manufacturing quartz crystal element

A method of manufacturing a quartz crystal element, the method comprising:

• preparing a quartz crystal wafer which has a predetermined cutting angle with respect to a crystal axis of a quartz crystal, and which has a first surface and a second surface having an obverse-reverse relationship;
• forming a first resist film on the first surface, the first resist film having a first tilted part tilted with respect to the first surface, and being dry-etched together with the quartz crystal;
• forming a first tilted surface tilted with respect to the first surface by dry-etching the quartz crystal wafer from the first surface;
• forming a second resist film on the second surface, the second resist film having a second tilted part tilted with respect to the second surface, and being dry-etched together with the quartz crystal;
• and
• forming a second tilted surface tilted with respect to the second surface by dry-etching the quartz crystal wafer from the second surface,
• wherein
• the quartz crystal element which is provided with the first tilted surface and the second tilted surface, and which has a cutting angle different from the predetermined cutting angle is formed,
• the quartz crystal wafer has a plurality of element areas where the quartz crystal elements are respectively formed, and
• the quartz crystal element formed from at least one of the element areas is different in thickness from the quartz crystal element formed from another of the element areas.