An FBAR device includes a substrate structure provided with an upper surface, a seed layer formed on the upper surface of the substrate structure and made of one selected from gold (Au) and titanium (Ti), and one or more acoustic resonant portions. Each of the acoustic resonant portions includes a lower electrode film formed on the seed layer and made of molybdenum (Mo), a piezoelectric layer formed on the lower electrode film and made of aluminum nitride (AlN), and an upper electrode film formed on the piezoelectric layer.