A method for adding a new game performance to a game wherein players enjoy operating own registered characters by inputting own accounts. The game performing method for performing a predetermined game wherein a plurality of players operates own registered characters by inputting own accounts, has: storing a plurality of characters including a registered character; storing play data of the plurality of characters; determining one character of the plurality of characters instead of the registered character to be a player character of a player according to an operation inputted by the player; selecting the registered character corresponding to an account of the player as a CPU character from the plurality of characters; and performing a fight of the CPU character selected against the player character determined by controlling an action of the CPU character on the basis of play data corresponding to the CPU character.