對於少年犯罪被害之重視，已爲現代各國刑事政策上所重視議題之一，日本亦不例外，特於九○年代末至二○○○年，伴隨少年法修正，日本國內更積極於少年犯罪預防與被害保護之推行。惟此時，日本國內仍發生「新潟少女囚禁案件」（最高法院平成15（あ）60號），本案加害人對被害人實施長達九年二個月之囚禁，其間並對被害少女除施加暴行與性侵害，被害人所造成心理傷害可謂巨大。基於國際間對於兒童及少年保護政策之重視，加上，近幾年國際間陸續發現少女監禁、性侵害之案件，本案加害人對於被害人所實施之囚禁、性侵害行爲，可謂有相當程度之研究重要性。承此，本文將聚焦本案加害人囚禁被害人之行爲層面，試圖以匯集心理學與社會學理文獻分析方式，以戀童症與家庭系統理論二個論點解析本案加害人實施拘禁與性侵害行爲之原因。

Internationally, juvenile delinquency has become one of the important issues in criminal policy. In Japan, due to the amendment of the juvenile law, the prevention of juvenile delinquency and the protection of victim of such offense had been positively advocated during the late 90s-2000. However, serious event such as "the imprisoned Niigata girl" still happened. In which case, the author of the injury had imprisoned the victim for nine years and two months, committed acts of violence and sexual assault, and left the girl with an injured mentality. This case bears academic significance and is hence worth deeper exploration since internationally policies of protecting children and juveniles have received great attention and similar events of imprisonment have been occurring worldwide. Adopting the traditional methodology in legal theory, namely, the documentary analysis, this paper focuses on the behavioral aspect of the Niigata case, trying to explain the acts of imprisonment and sexual assault by the contention of pedophilia and family system theory.