According to one embodiment, a photovoltaic system contains a photovoltaic element comprising a photoelectromotive force part, a first transmitting member, and a second transmitting member, the photoelectromotive force part having a light transmitting property and generating an electromotive force by light irradiation, the first transmitting member and the second transmitting member being arranged at both sides of the photoelectromotive force part in a thickness direction, light transmittances of the first transmitting member and the second transmitting member being electrically changed; a control part configured to maximize a power generation amount of the photovoltaic element by changing the respective light transmittances of the first transmitting member and the second transmitting member while a light transmittance of a whole photovoltaic element is kept constant.