The universality of secure base construct, which suggests that one’s use of an attachment figure as a secure base from which to explore the environment is an evolutionary outcome, is one of the core ideas of attachment theory. However, this universality idea has been critiqued because exploration is not as valued in Japanese culture as it is in Western cultures. Waters and Waters (2006) hypothesized that one’s experiences of secure base behaviors are stored as a script in memory, and developed a narrative assessment called the Attachment Script Assessment (ASA) to evaluate one’s secure base script. This study examined the validity of the ASA and the utility of secure base concept in Japanese culture. A sample of Japanese young adults (N = 89; M = 23.46; SD = 3.20; 57% = females) completed both the ASA and self-report questionnaires. The results revealed that the ASA score was associated with two dimensions of self-report questionnaires assessing parent–youth attachment relationships (trust and communication). The ASA score was not related to Japanese cultural values (amae acceptance, interdependent self-construal, and low independent self-construal). However, a low ASA score was related to a psychological dysfunction in the Japanese cultural context; hikikomori symptoms, which are defined as a desire to remain in his or her own room and his or her understanding of this behavior in other people. We concluded that since hikikomori can be interpreted as an extreme inhibition of exploration, the association between low secure base script and hikikomori symptoms suggests the utility of secure base construct in Japan.