Although volunteering has attracted attention in Japan as a useful measure for evaluating the level of senior citizens'self-rated health and satisfaction, no study has focused on the benefits of volunteering by Japanese senior citizens. To elucidate the effects of volunteering by Japanese women on their own well-being, we collected data from 106 volunteers and 60 non-volunteers aged 60 years or over using a self-administered questionnaire that included questions about sociodemographic characteristics, physical conditions, self-rated health, meaning and satisfaction in life, and emotional support network. Significant differences were observed between the volunteer group and the non-volunteer group in "self-rated health," "frequency of consulting doctors," and "frequency of communicating with friends." Also, total score of "source of meaning and satisfaction in life" and total score of "emotional support network" were significantly higher in the volunteer group than in the non-volunteer group. After adjusting for the effects of other factors, "frequency of consulting doctors" and "emotional support network" remained significantly associated with the frequency of being a voluntary worker. The present study suggests that volunteering might partially contribute to improving the well-being of senior citizens. Further studies are needed to clarify the effects of volunteering on the well-being of senior citizens in an aging society.