The purpose of this study was to investigate and analyze whether chatbots promote deeper self-disclosure than close friends, and the relationship between deeper self-disclosure to chatbots, avoidance of negative evaluation from others and self-esteem. A questionnaire survey was conducted to 194 adolescents who had experienced self-disclosure to chatbots. The results suggested that chatbots were more likely to engage in deep self-disclosure than close friends in this study. This suggests the effectiveness of chatbots as a means of deep self-disclosure. No significant relationship was found between deep self-disclosure to chatbots and avoidance of negative evaluation from others. On the other hand, a significant negative association was found between deep self-disclosure to the chatbot and self-esteem, indicating that people with low self-esteem were encouraged to deep self-disclose to the chatbot more than those with high self-esteem. Thus, the results suggest that self-esteem is deeply related to the background that prompts deeper self-disclosure to chatbots than to close friends.