Provided is a hetero-junction solar cell with a silicon crystalline substrate of small thickness but exhibiting less warpage, and having a high photoelectric conversion efficiency. The crystalline silicon substrate has a thickness of 50 μm to 200 μm, and has a rough structure on the light-incident-side surface thereof. The surface of the transparent conductive layer in the light incidence side has an irregular structure. The top-bottom distance in the irregular structure of the transparent conductive layer in the light-incidence-side is preferably smaller than the top-bottom distance in the rough structure of the crystalline silicon substrate in the-light-incidence side. The distance between tops of the projections in the irregular structure on the surface of the transparent conductive layer in the light incidence side is preferably smaller than the distance between tops of the projections in the rough structure on the surface of the crystalline silicon substrate in the light incidence side.