N symbol arrays are scrolled in M rows and N columns of display regions. In each of the symbol arrays, a normal symbol same as a certain normal symbol does not exist within (M−1) rows above and below the certain normal symbol. Therefore, two or more of the same normal symbols are not displayed in each column of display regions, and a maximum of N of the same normal symbols are displayed in all the display regions. Further, the same normal symbols as those present within (M−1) rows above and below the special symbol included in one symbol array do not exist within (M−1) rows above and below the special symbols included in the other symbol arrays. Therefore, when N of the same normal symbols are displayed, a maximum of one special symbol is displayed.