When a direction is input through a direction indicating switch of an operation switch unit, a player character of a game, such as, but not limited to, for example a basketball game, moves in the inputted direction while dribbling a ball. When a direction directed toward the position of the ball from the position of the player character matches with the inputted direction, the moving speed of the player character becomes V. When the direction directed toward the position of the ball from the position of the player character does not match with the input direction, the moving speed of the player character becomes Vcos(θ/2) where θ is an angle defined by the direction directed toward the position of the ball from the position of the player character and the inputted direction.