When a racing form speculating a race is selected, a bet is automatically made on a speculated possible finish place. A racing form speculated information indication region K1 is provided on the right side of a speculation indication region H5. A speculation racing form indication region K2 is provided on the right side of the racing form speculated information indication region K1. A game player selects a racing form to be used as speculated information. When an all bets button K5 below a racing form release button K4, bets are made maximum 8 sets of horse number combinations speculated by the racing forms. The bet control method can permit game players to easily and quickly bet.