Disclosed is a controller for controlling short-circuit across positive and negative terminals of a dye sensitized solar cell for converting a light energy into an electrical energy. The controller includes: a voltage detecting section detecting a voltage developed across the positive and negative terminals of the cell; a current detecting section detecting a current caused to flow through the positive terminal of the cell; a judging section judging how a power generation state of the cell is, and whether or not a release state is provided across the positive and negative terminals of the cell in accordance with a value of the voltage detected by the voltage detecting section and a value of the current detected by the current detecting section; and a short-circuiting/releasing section short-circuiting or releasing across the positive and negative terminals of the cell in accordance with a result of the judgment made by the judging section.