An acceleration sensor has a piezoelectric element which includes a piezoelectric member layer in which a plurality of piezoelectric members are stacked and electrodes which are disposed in major opposed surfaces of the piezoelectric member layer; and a support member for supporting the piezoelectric element, wherein some piezoelectric members of the piezoelectric member layer are polarized. The electrodes are disposed in both surfaces of the polarized piezoelectric members. Capacitors which are formed by the polarized piezoelectric members and the electrodes in both surfaces of the polarized piezoelectric members are connected parallel to each other.