高額療養費は、計算期間において、基準日被保険者又はその被扶養者がそれぞれ当該保険者の被保険者又はその被扶養者として受けた療養（法第九十八条第一項（法第百十条第七項及び第百十一条第三項において準用する場合を含む。）の規定による保険給付に係る療養（次項及び第四十三条の二において「継続給付に係る療養」という。）を含む。）に係る次に掲げる額の合算額（第四十一条第一項から第五項まで又は前条の規定により高額療養費が支給される場合にあっては、当該支給額を控除した額とし、法第五十三条に規定するその他の給付として次に掲げる額に係る負担を軽減するための金品が支給される場合にあっては、当該金品に相当する額を控除した額とする。）から七十歳以上年間世帯支給総額（次項に規定する七十歳以上一部負担金等年間世帯合算額から同項の七十歳以上年間高額療養費算定基準額を控除した額（当該額が零を下回る場合には、零とする。）をいう。）を控除した額（以下この項において「一部負担金等年間世帯合算額」という。）が高額療養費算定基準額を超える場合に基準日被保険者に支給するものとし、その額は、一部負担金等年間世帯合算額から高額療養費算定基準額を控除した額とする。
High-cost medical expenses are to be paid to the insured person on the reference date where the amount obtained by deducting the total annual household payment for persons aged 70 or over (meaning the amount obtained by deducting the annual base amount for calculating high-cost medical expenses for persons aged 70 or over under paragraph (2) from the annual household total of co-payments, etc. for persons aged 70 or over prescribed in that paragraph (or zero, if that amount is less than zero)) from the total sum of the following amounts relating to medical treatment that the insured person on the reference date or the dependents thereof respectively received during the calculation period as an insured person of the relevant insurer or as dependents thereof (including medical treatment relating to insurance benefits under Article 98, paragraph (1) of the Act (including as applied mutatis mutandis under Article 110, paragraph (7) and Article 111, paragraph (3) of the Act) (referred to in the following paragraph and Article 43-2 as "medical treatment under continued benefits")) (where high-cost medical expenses are paid pursuant to Article 41, paragraphs (1) through (5) or the preceding Article, the amount after deducting the amount paid, and where money or goods to reduce the burden relating to the following amounts are provided as other benefits prescribed in Article 53 of the Act, the amount after deducting the amount equivalent to that money or those goods) (hereinafter referred to as the "annual household total of co-payments, etc." in this paragraph) exceeds the base amount for calculating high-cost medical expenses, and the amount of those expenses is to be the amount obtained by deducting the base amount for calculating high-cost medical expenses from the annual household total of co-payments, etc.