The turning point of development around the ages of 9 and 10 years is especially critical for high-functioning pervasive developmental disorders (HFPDD) children. In this study, in order to grasp their fundamental needs, their unique way to understand others' mind was considered in light of the type of mentalization and compensatory strategies. While typically developing children acquire the theory of mind around 4 years of age based on intuitive mentalization, HFPDD children achieved it at last around 9 years of mental age depending only on propositional mentalization. To compensate their lack of intuitive mentalization, HFPDD children manage to anticipate others' behavior using verbal ability. Propositional mentalization without intuitive mentalization make them possible to speculate others' mind, but also often let them to misunderstand others. As a result, it was suggested that there are three fundamental needs for HFPDD children: (1) to reassure themselves about their relationship with others, (2) to acquire a sense of achievement, and (3) to develop their communication competence. It was finally indicated that clarifying the form and role of their speech is the important challenge in order to understand their internal world.