To provide a novel glass composition having the property of browning substantially improved, while securing an adequate X-ray absorption property and while suppressing devitrification of a panel glass to a practically problem-free level, in preparation for higher voltage and larger current for projection type cathode ray tubes. A panel glass for cathode ray tube, having a glass composition containing substantially no PbO, and more than 10 mass % and at most 15 mass % of ZnO, wherein (MgO (mass %)+ZnO (mass %))/(SrO (mass %)+BaO(mass %)+CaO (mass %))>0.55, and wherein when the sum of Na2O (mol %), K2O (mol %) and Li2O (mol %), as represented by mol percentage, is represented by R2O, 0.15≦Na2O (mol %)/R2O≦0.25, and 0.45≦K2O (mol %)/R2O≦0.55, and the linear absorption coefficient of X-ray having a wavelength of 0.06 nm is at least 36.0 cm−1.