The present invention relates to a piezoelectric resonator and a manufacturing method thereof, and a cover for piezoelectric resonator. The object of the present invention is to provide a cover for a piezoelectric resonator having a difficult to break light transmission window component. A piezoelectric resonating plate comprises a resonating arm and a first and a second metal film formed on the resonating arm. The cover for piezoelectric resonator comprises: a frame comprising a through hole, a light transmission component with parallel-arranged a upper surface and a lower surface located inthe through hole, wherein the lower surface of the light transmission component are arranged to oppose with the second metal film. The through hole is disposed at an open end part of at least one of the surface and the back, has a curved inner wall face connected by a curved face and surface or back, and has a vertical inner wall face which is vertical to the surface and back of the one part of the frame along the thickness direction. The light transmission component is contacted closely with at least a part of the vertical inner wall face and at least a part of the curved inner wall face.