This article concerns new policy challenges relevant to companies in supporting working carers of older people to retain their jobs in Japan. Although long-term leave and flexible working measures have been reformed to address long-term in-home care, the results of new data analysis imply that the effectiveness of support measures differs according to the length of the period of care provided at home. Long-term leave and reducing working hours are effective if the period in which care is provided is relatively short, but when care at home lasts longer, flexibility in the working schedule is crucial. The results also signal the importance of addressing the health of working carers as a new challenge that arises regardless of the length of care at home.