A surface mounting quartz crystal unit includes a ceramic substrate, a holding terminal, a metal cover, a signal line terminal and a ground terminal, and a metal layer. The holding terminal holds a crystal resonator on the substrate. The metal cover is arranged to cover the crystal resonator. The signal line terminal and a ground terminal are formed on a rear surface of the substrate. The metal layer bonds the substrate to the metal cover at a part on a front surface of the substrate. The part is in contact with the metal cover. The substrate has a first through via inside the substrate. The first through via connects the holding terminal to the signal line terminal. The substrate has a through conductor at the substrate. The through conductor connects the metal layer to the ground terminal.