In a game machine, a reel unit is disposed behind each display window. The reel unit has an outer reel and an inner reel which coaxially rotate. The inner reel carries plural inner symbols at a certain pitch. The outer reel carries plural but less outer symbols. The outer symbol has a larger size than the inner symbol, and is opaque. The outer symbol on the inner symbol hides the inner symbol. A symbol combination is formed of only plural inner symbols, or at least one of the inner symbols and at least one of the outer symbols.