a solid - state imaging element including : a plurality of unit pixels each having a photoelectric conversion part , a transfer part that transfers a charge generated by the photoelectric conversion part to a predetermined region , and a draining part that drains a charge in the predetermined region ; a light shielding film being formed under an interconnect layer in the unit pixels and shield , from light , substantially the whole surface of the plurality of unit pixels except a light receiving part of the photoelectric conversion part ; and a voltage controller controlling a voltage applied to the light shielding film . the voltage controller sets the voltage applied to the light shielding film to a first voltage in charge draining by the draining part and sets the voltage applied to the light shielding film to a second voltage higher than the first voltage in charge transfer by the transfer part .