The purpose of the present study was to develop a Japanese version of Rumination-Reflection Questionnaire (RRQ) and examine its reliability and validity. Previous studies suggested that RRQ had two subscales: rumination and reflection. Rumination was dispositional self-attentiveness evoked by negative events, and reflection was dispositional self-attentiveness motivated by intellectual interests. Data from 241 undergraduates were analyzed, and factor analysis showed two factors, corresponding to the previous findings. Both subscales showed sufficient internal consistency and concurrent validity with clinical and personality scales. These findings provided support for reliability and validity of Japanese-version RRQ.