To form fresh computer game software reflecting the mental stage of and interest by a user simply when the user plays a computer game.

The computer game software (A) 1 progresses the game according to a scenario B, forms data #1 to data #n, according to the action patterns that the user himself or herself takes, in the process that the user plays the game. The computer provides the computer software (C) 5 with such data. The computer software (C) 5 makes the respective elements of the data N consisting of the data #1 to data #n correspondent to the constitution elements #1 to constitution elements #n, such as the subject of the game, the characters of the hero or heroine, a stage and enemy characters which are the fundamentals of a computer game software (X) 7 to be freshly formed. The software (C) 5 provides the computer game software (X) 7 with the data described above. The computer game software (X) 7 determines the constitution elements #1 to constitution elements #n in accordance with the respective elements of the data N provided from the computer software (C) 5.