A crystal resonator includes: lower glass plates on which first electrodes are formed so as to extend from side surfaces to a bottom surface of the lower glass plates; a crystal plate which is provided over the lower glass plates and on which second electrodes to be coupled to the first electrodes are formed on a surface in contact with the lower glass plates; and an upper glass plate which is provided over the crystal plate; wherein the side surfaces of the lower glass plates on which the first electrodes are formed are provided with a protrusion that extends in parallel with a top surface and the bottom surface of the lower glass plates and that extends from one end to the other end of each of the side surfaces, and wherein the first electrodes are formed on the side surfaces that include surfaces of the protrusion.