The purpose of the present study was to develop the Depressive Rumination Interview Task (DRI task), an interview method to assess the perseveration of depressive rumination, and to investigate the validity of rumination steps emitted in the task. Sixty one undergraduate and graduate students participated in the study. Participants completed self-report measures of depressive rumination (Negative Rumination of the Japanese version of the Response Styles Questionnaire) and depression (the Japanese version of the Zung Self-Rating Depression Scale). They also undertook the DRI task. In this task, participants answered the questions “Why is it that X makes you feel depressed?”, where X was either the initial topic of depression they mentioned, or their response at the previous step. The number of rumination steps emitted in the DRI task significantly positively correlated with depression (r=.29, p<.05), and marginally significantly positively correlated with self-report measure of depressive rumination (r=.24, p<.10). These results suggested moderate validity of rumination steps. It was suggested that refinement of the DRI task and re-examination of the validity of rumination steps emitted in the task were needed. Improved assessment methods of depressive rumination will contribute to a better understanding of this perseverative negative thinking.