In Japan, which is thought to be a rapidly growing super-aging society, a national campaign named “the Dementia Supporter Caravan” has been deployed. The aim of this study was to assess the educational benefits of the dementia supporter training program for nurses and nursing students. We conducted dementia supporter training, and measured knowledge and attitudes regarding people with dementia as educational benefits pre- and post-training. Data sets of 134 nursing students and 63 nurses were analyzed. The results indicated that the two groups gained knowledge, understanding, and the confidence to care for people with dementia after attending the dementia supporter training program. Moreover, the two groups derived different benefits from the program. Nursing students gained substantial knowledge and learnt the importance of early detection and treatment, to levels similar to those of nurses prior to training. The training program reduced the difficulties of nurses to interact with and care for people with dementia. We can conclude that the dementia supporter training program has considerable educational benefits for nurses and nursing students.