A photoelectric converter comprising a photosensor element, a typical example of the photosensor element comprising: a transistor including an n or n.sup.+ collector region an n.sup.- region disposed contiguous to the collector region, a p base region disposed contiguous to the n.sup.- region, an n.sup.+ emitter region disposed contiguous to the base region, and a first electrode connected to the emitter region; and a storage capacitor constituted by the base region, an electrically insulating region disposed contiguous to the base region, and a second electrode connected to the electrically insulating region; whereby the base region is held in a floating state. A photogenerated charge is stored in the base region by controlling the potential of the base region and an electric signal corresponding to the charge stored in the base region is subsequently output from the first electrode.