The glass substrate for a solar cell of the present invention is characterized by having a glass composition including, in terms of mass %, 50 to 80% of SiO2, 5 to 20% of Al2O3, 0 to 20% of B2O3, 0 to 20% of MgO, 0 to 20% of CaO, 0 to 20% of SrO, 0 to 20% of BaO, 0.001 to 2% of SnO2, 0 to 1% of As2O3, having a mass ratio SnO2/(Fe2O3+SnO2) of 0.9 or more, and having a difference between transmittances at a wavelength of 400 nm before and after irradiation with ultraviolet ray of 2% or less.