A quartz crystal unit that includes a quartz crystal resonator with a quartz crystal blank on which a pair of excitation electrodes are formed, a frame body that surrounds an outer periphery of the blank, and a coupling member that couples the frame body to the blank. Moreover, a package member is joined to an entire periphery of the frame body on at least one side of the excitation electrodes; and an extension electrode is provided that is electrically connected to one of the excitation electrodes. A recess is formed in a junction region of at least one of the frame body and the package member. In the junction region, the extension electrode is disposed in the recess in such a way that the extension electrode has a thickness that does not exceed a depth of the recess.