To solve the problem that the conventional game machines can make a sudden end of a special game advantageous for players when the game operation is made without grasping game situations.

A sub CPU82 judges whether a demonstration command transmitted from the main control board 61 is received or not (S341) and when "Yes" is given by the judgment, subsequently, it is judged whether the ongoing BB (big bonus) operation flag or the ongoing MB operation flat is "on" or not (S342). When "Yes" is given by the judgment, the sub CPU82 carries out a demonstration screen display lottery (S343). When the lottery is won (S344), it displays a value obtained by subtracting the value of a number of game media counter at the end of the BB bonus from the number "345" of put-out possible game media in the BB game or a value obtained by subtracting the value of a number of game media counter at the end of MB bonus from the number "253"of put-out possible game media in the MB game on a liquid crystal display device 22 together with a demonstration screen (S345).