A piezoelectric device has: a ceramic substrate having a first principal surface and a second principal surface opposed to each other; a piezoelectric element arranged on the first principal surface; a frame having a first face and a second face opposed to each other and arranged on the ceramic substrate so as to surround the piezoelectric element; a metal layer arranged on the second face of the frame; and a metal lid arranged on the metal layer so as to close a space surrounded by the frame. The first face of the frame is in contact with the first principal surface of the ceramic substrate. The metal layer and the metal lid are joined to each other by resistance welding. The frame has a composite portion containing a metal and a metal oxide and the composite portion includes the second face and is in contact with the metal layer.