A piezoelectric element includes a piezoelectric layer, a first electrode layer, and a second electrode layer. The piezoelectric layer includes first and second surfaces opposed to each other. The first electrode layer is located on the first surface. The second electrode layer is located on the second surface. At least a portion of the second electrode layer faces the first electrode layer with the piezoelectric layer interposed therebetween. The second electrode layer mainly includes silicon. The piezoelectric layer is monocrystalline.