NOVELTY - Alkali-free glass has strain point of 680 degrees C or more, average coefficient of thermal expansion of 30x 10-7 to 43x 10-7/( degrees C) at 50-350 degrees C, temperature (T2) at which glass viscosity is 102dPa.second, of 1670 degrees C or less, and temperature (T4) at which glass viscosity is 104 dPa.second of 1320 degrees C or less, and mass decrease of 3.1 mg/cm2 or more, when the alkali-free glass is immersed in etching liquid containing hydrofluoric acid which is obtained using 5% hydrofluoric acid aqueous solution, for 20 minutes. The ratio of magnesium oxide and calcium oxide is 1.05 or more.    USE - Alkali-free glass is used for display board, substrate for photomasks, substrate for magnetic disks and substrate for solar cells.    ADVANTAGE - The alkali-free glass has high strain point, low viscosity, high etching speed and high ease of float molding.    DETAILED DESCRIPTION - Alkali-free glass has strain point of 680 degrees C or more, average coefficient of thermal expansion of 30x 10-7 to 43x 10-7/( degrees C) at 50-350 degrees C, temperature (T2) at which glass viscosity is 102dPa.second, of 1670 degrees C or less, and temperature (T4) at which glass viscosity is 104 dPa.second, of 1320 degrees C or less, and mass decrease of 3.1 mg/cm2 or more, when the alkali-free glass is immersed in etching liquid containing hydrofluoric acid which is obtained using 5% hydrofluoric acid aqueous solution, for 20 minutes. The alkali-free glass comprises 60-70 mol% silicon dioxide, 11-16 mol% aluminum oxide, 0-1.5 mol% boron trioxide, 7-12 mol% magnesium oxide, 0-7 mol% calcium oxide, 4.5-10 mol% strontium oxide, 0-0.5 mol% barium oxide and 16-22 mol% total content of magnesium oxide, calcium oxide, strontium oxide and barium oxide, and in which the ratio of total content of silicon dioxide and aluminum oxide and total content of magnesium oxide, calcium oxide, strontium oxide and barium oxide is 4.7 or less, the ratio of magnesium oxide and calcium oxide is 1.05 or more, ratio of strontium oxide and calcium oxide is 1.05 or more, and the ratio of total content of magnesium oxide and strontium oxide and total content of magnesium oxide, calcium oxide, strontium oxide and barium oxide is 0.7 or more.