Background: According to the diversification of the health needs and the expansion of health disparities, public health nurses need to improve their practical capabilities, starting from basic education in graduate and undergraduate courses. And Reflective Practice with using reflective journal is one way of improving practical capabilities. The purpose of this study was to investigate the relationship between the volume of reflective journal and the quality of progress in the reflective cycle. Methods: The participants in this study were 20 junior students majoring in public health nursing (hereinafter "PHN students") at a university in the Chugoku area, Japan. We asked the participants to answer the questions on Reflective Practice Skills (RPS) composed of six criteria corresponding to the six questions of Gibbs on the reflective cycle before and after they started writing RJ. The volume of reflective writing was measured by the number of characters written by the PHN students in RJ of the reflective practice for three months. The study plan was approved by the Ethics Committee for Nursing Study, Okayama University. Results: Although the average total RPS score showed a change of about 3 points as a result of the 3-month RJ writing exercise, no correlation was observed between the RPS score and the RJ writing volume (r = 0.175). However, we did observe a moderately positive correlation between the RPS score and the RJ writing volume with regard to Items 5 and 6 (r = 0.475 and r = 0.444, respectively). Conclusion: This study indicated that detailed RJ writing helps to complete the reflective cycle all the way to theorization and action planning, and that the volume of writing may serve as a criterion for qualitative evaluation.