第四十五条の三（三月以外の月から用いる都道府県単位保険料率の算定方法）
Article 45-3Method of Calculating the Premium Rate for Each Prefecture to Be Used from a Month Other than March
Notwithstanding the provisions of the preceding Article, when JHIA intends to use a premium rate for each prefecture that it is about to change from a month other than March, JHIA is to calculate that premium rate for each prefecture, as specified by Order of the Ministry of Health, Labour and Welfare, by dividing the amount obtained by dividing the amount obtained by deducting the amount listed in item (ii) from the amount listed in item (i) by the projected premium payment rate by the amount listed in item (iii).
the amount listed in item (i) of the preceding Article in the business year to which the first month in which the premium rate for each prefecture after the change is to be used (referred to as the "month of application" in the following item and item (iii)) belongs;
当該変更後の都道府県単位保険料率を用いる最初の月（次号及び第三号において「適用月」という。）の属する事業年度における前条第一号に掲げる額
the amount specified respectively in (a) through (c) in accordance with the classification of months of application listed in (a) through (c):
次のイからハまでに掲げる適用月の区分に応じ、それぞれイからハまでに定める額
a month other than a month listed in (b) or (c): the amount obtained by multiplying the estimated amount of the total sum of the total amount of the total remuneration of the branch-insured person concerned (excluding insured persons with optional and continued coverage) for each month from March of the business year previous to the business year to which the month of application belongs through the month preceding the month of application, and the total amount of the total remuneration of the branch-insured person concerned (limited to insured persons with optional and continued coverage) for each month from April of the business year to which the month of application belongs through the month preceding the month of application, by the premium rate for each prefecture before the change, and then multiplying the amount so obtained by the projected premium payment rate in the business year to which the month of application belongs;
ロ又はハに掲げる月以外の月 適用月の属する事業年度の前事業年度の三月から当該適用月の前月までの各月の当該支部被保険者（任意継続被保険者を除く。）の総報酬額の総額及び当該適用月の属する事業年度の四月から当該適用月の前月までの各月の当該支部被保険者（任意継続被保険者に限る。）の総報酬額の総額の合算額の見込額に当該変更前の都道府県単位保険料率を乗じて得た額に当該適用月の属する事業年度における予定保険料納付率を乗じて得た額
April: the amount obtained by multiplying the estimated amount of the total amount of the total remuneration of the branch-insured person concerned (excluding insured persons with optional and continued coverage) for the month preceding that April by the premium rate for each prefecture before the change, and then multiplying the amount so obtained by the projected premium payment rate in the business year to which that April belongs;
四月 当該四月の前月の当該支部被保険者（任意継続被保険者を除く。）の総報酬額の総額の見込額に当該変更前の都道府県単位保険料率を乗じて得た額に当該四月の属する事業年度における予定保険料納付率を乗じて得た額
May: the amount obtained by multiplying the estimated amount of the total sum of the total amount of the total remuneration of the branch-insured person concerned (excluding insured persons with optional and continued coverage) for the month two months before that May and the month preceding that May, and the total amount of the total remuneration of the branch-insured person concerned (limited to insured persons with optional and continued coverage) for the month preceding that May, by the premium rate for each prefecture before the change, and then multiplying the amount so obtained by the projected premium payment rate in the business year to which that May belongs;
五月 当該五月の前々月及び前月の当該支部被保険者（任意継続被保険者を除く。）の総報酬額の総額並びに当該五月の前月の当該支部被保険者（任意継続被保険者に限る。）の総報酬額の総額の合算額の見込額に当該変更前の都道府県単位保険料率を乗じて得た額に当該五月の属する事業年度における予定保険料納付率を乗じて得た額
the estimated amount of the total sum of the total amount of the total remuneration of the branch-insured person concerned (excluding insured persons with optional and continued coverage) for each month from the month of application through February of the business year to which the month of application belongs (where the month of application is February, that February), and the total amount of the total remuneration of the branch-insured person concerned (limited to insured persons with optional and continued coverage) for each month from the month of application through March of the business year to which the month of application belongs.
定義第四十五条の二第一項・この規定及び第四十五条の三の中だけ
一の事業年度の三月分から当該一の事業年度の翌事業年度の二月分までの保険料（任意継続被保険者に係る保険料にあっては、当該翌事業年度の四月分から三月分までの保険料）として徴収すべき額の見込額に占める当該翌事業年度において納付が見込まれる保険料の額の総額の割合として厚生労働省令で定めるところにより算定される率
わかりやすく言うと
全国健康保険協会が都道府県単位保険料率の算定に使う率で、ある事業年度の三月分から翌事業年度の二月分まで（任意継続被保険者は翌事業年度の四月分から三月分まで）の保険料の徴収見込額のうち、翌事業年度に納付が見込まれる額の割合です。算定方法は厚生労働省令で定められます。
定義第四十五条の二第一項・この規定及び第四十五条の三及び第四十五条の四第四項第一号の中だけ
法第百六十条第二項に規定する都道府県単位保険料率
わかりやすく言うと
全国健康保険協会が、千分の三十から千分の百三十までの範囲内で、支部被保険者を単位として決め、その支部被保険者に適用する一般保険料率のことです（健康保険法第百六十条第一項、第二項）。
定義第四十五条の二第一項第一号イ
同条第一項に規定する支部被保険者
わかりやすく言うと
全国健康保険協会のその支部の都道府県にある適用事業所に使われる被保険者と、その都道府県の区域内に住所か居所がある任意継続被保険者のことです（健康保険法第百六十条第一項）。
略称規定第四十五条の三第一項第一号・この規定及び第四十五条の三第一項第二号及び第三号の中だけ
当該変更後の都道府県単位保険料率を用いる最初の月（次号及び第三号において「適用月」という。）の属する事業年度における前条第一号に掲げる額
わかりやすく言うと
全国健康保険協会が都道府県単位保険料率を変更して三月以外の月から用いようとするときの、変更後の料率を用いる最初の月のことです。