A game is executed in a normal round, in a first-type free round, and in a second-type free round. The normal round is executed with a first symbol set including a plurality of symbols. The first-type free round is executed with a second symbol set that includes at least one first symbol in addition to the symbols in the first symbol set. The second-type free round is executed with a third symbol set that includes at least one second symbol in addition to the symbols in the first symbol set, the at least one second symbol being different from the at least one first symbol.