We used the database to include 570,434 person-month records of 23,879 insured individuals. Conducted difference-in-difference estimations to clarify the difference in long-term care and medical care usage and expenditure before and after the change in the copayment limit for qualifying individuals from 10% to 20% in August 2015 in Japan. The increase in insured individuals' copayment would appear to be a "balloon effect" between long-term care and medical service.