Float bath roof member and apparatus for manufacturing float glass plate using the same

PROBLEM TO BE SOLVED: To provide a float bath roof member having creep deformation suppressed during use, and an apparatus for manufacturing a glass plate using the same.SOLUTION: The float bath roof member has 90 mass% or more of a mullite phase out of respective crystal phases, consists of an alumina silica based sintered body having 2 or less mass% of the total content of sodium oxide, potassium oxide, titanium oxide and iron oxide and is constituted of coarse grains having an average grain size D50 of 1.0 mm or more and fine grains having an average grain size D50 of 0.1 mm or less. Mass ratios of the coarse grains and the fine grains are 85-60 mass% and 15-40 mass%, respectively.SELECTED DRAWING: None