1. A method of generating a character image in which multiple characters, including a player character, a three-dimensional character drawn by three-dimensional polygon data and a two-dimensional character drawn by two-dimensional sprite data, are drawn in a virtual three-dimensional space, the character image being used for displaying a conversation field in which the player character is allowed to have a conversation with other character, the method comprising: determining that a character satisfying a predefined non-display condition is not drawn in the virtual three-dimensional space among characters positioned in a field of view of a virtual camera; drawing a character that satisfies a predetermined two-dimensional display condition as a two-dimensional character among the characters positioned in the field of view of the virtual camera; and drawing a character that does not satisfy the two-dimensional display condition as a three-dimensional character among the characters positioned in the field of view of the virtual camera.