A substrate for p-Si TFT flat panel displays made of a glass having a high low-temperature-viscosity characteristic temperature and manufactured while avoiding erosion/wear of a melting tank during melting through direct electrical heating. The glass substrate comprises 52-78 mass % of SiO2, 3-25 mass % of Al2O3, 3-15 mass % of B2O3, 3-20 mass % of RO, wherein RO is total amount of MgO, CaO, SrO, and BaO, 0.01-0.8 mass % of R2O, wherein R2O is total amount of Li2O, Na2O, and K2O, and 0-0.3 mass % of Sb2O3, and substantially does not comprise As2O3, wherein the mass ratio CaO/RO is equal to or greater than 0.65, the mass ratio (SiO2+Al2O3)/B2O3 is in a range of 7-30, and the mass ratio (SiO2+Al2O3)/RO is equal to or greater than 5. A related method involves melting glass raw materials blended to provide the glass composition; a forming step of forming the molten glass into a flat-plate glass; and an annealing step of annealing the flat-plate glass.