As his name suggests, the vain man is a symbol of vanity. When the little prince arrives on the vain man's planet, the vain man assumes that the prince is an admirer; as the narrator explains, "to conceited men, all other men are admirers." Desperate for attention and approval, the vain man derives his worth from external praise. He even makes the little prince clap for him so that he can take off his hat and salute. He is desperate to be considered the ideal, and explains to the little prince that "to admire means that you regard me as the handsomest, the best-dressed, the richest, and the most intelligent man on this planet." However, his logic is nonsensical, because to ensure his superiority, he must exist in isolation. Like other characters, including the king and the little prince, the vain man is the sole inhabitant of his planet.
Saint-Exupéry uses the vain man to critique adult society. The vain man is obsessed with recognition and praise, yet he has done nothing truly admirable to earn such attention. This highlights how, in adult society, a desire for praise doesn’t always match the worthiness of those who desire it. Furthermore, his entire existence is a paradox; he depends on others for validation, yet he is utterly alone. Saint-Exupéry suggests that simply growing up does not guarantee wisdom or insight. The vain man's behavior prompts the Little Prince to reflect, "The grown-ups are certainly very odd."