A solar cell includes a first photoelectric conversion part, a second photoelectric conversion part, a side insulating layer, a first electrode, and a second electrode. The first photoelectric conversion part includes a photoelectric conversion layer composed of a perovskite compound, a first transport layer on one side of the photoelectric conversion layer, and a second transport layer on the other side of the photoelectric conversion layer. The second photoelectric conversion part is arranged below the second transport layer of the first photoelectric conversion part and has a different material or structure from the first photoelectric conversion part. The side insulating layer is formed as a side surface surrounding the first photoelectric conversion part. The first electrode is electrically connected to the first photoelectric conversion part on one surface of the first photoelectric conversion part serving as a light-receiving surface. The second electrode is electrically connected to a bottom of the second photoelectric conversion part. Therefore, moisture permeability can be suppressed through the side insulating layer while an active region of the tandem structure solar cell is ensured to a maximum extent, thereby improving reliability.