A photoelectric conversion device designed according to a ratio of a line width to a pitch of a grid collector electrode is provided. The photoelectric conversion device includes a first substrate, a second substrate facing the first substrate, and a first electrode between the first substrate and the second substrate, the first electrode including a first grid electrode. A first ratio (W/P) of a line width of the first grid electrode to a pitch of the first grid electrode is configured in accordance with a photoelectric conversion efficiency of the photoelectric conversion device, thereby the photoelectric conversion device may have improved photoelectric conversion efficiency.