To provide a method for manufacturing a quartz piece which can suppress the deterioration of the CI and the temperature characteristic failure by forming the end surface of the quartz piece perpendicularly. A method for manufacturing a quartz piece that has a shape having two sides facing each other from a quartz substrate, includes the steps of: forming an etching mask provided with an opening area for forming the outside shape along one side out of the two sides which face each other, and provided with no opening area on the other side out of the two sides facing each other, on one surface side of the quartz substrate; and forming an etching mask provided with an opening area for forming an outside shape along the other side out of the two sides which face each other, and provided with no opening area on the one side, on the other surface side of the quartz substrate. Formation of protrusions is reduced when, at the time of etching from one surface side of the quartz substrate, the rate of etching in the direction from the one side toward the other side is greater than the rate of etching in the direction from the other side toward the one side due to the anisotropy of quartz, and at the time of etching from the other surface side of the quartz substrate, the rate of etching in the direction from the other side toward the one side is greater than the rate of etching in the direction from the one side toward the other side due to the anisotropy of quartz.