消費税がもたらす負担の構造とそれを表現する複数の尺度 / Structure of Burdens Caused by the Japanese Consumption Tax and Some Scales That Measure Those Burdens

The Japanese Consumption Tax (JCT) system is so designed that a seller of a product, who bears the liability of the tax, is to raise the selling price by the amount of tax to shift the tax burden to the buyer, and that the accumulated burden is finally borne by the consumer. The theory of indirect taxation regards the amount of price rise caused by a tax as the tax burden of the buyer. But the "included tax" price shown on a receipt represents merely 8/108 of the total price (in case of 8-percent tax rate) and is not necessarily the amount of price rise cased by the tax. Thus the amount of tax shifted from the seller to the buyer in each transaction is unclear. Taxation is intrinsically restriction on the property rights of people. This unclearness is a serious problem from the viewpoint of human rights. To approach this problem, the authors have proposed two scales for tax burdens, namely, legal burden and earning burden, and have given a preliminary discussion for the general public to organize burdens cased by JCT. In this paper, we elaborate their meanings in a more precise and learned manner. Legal burden represents the burden of private economic entity whose property is transferred to the government as a tax. Earning burden represents the burden of entity who cost something (such as effort) to earn money from the market. The present study shows the following observations: legal burden is not shifted in market transactions at all and is borne solely by the seller who is obliged to pay the tax; price change caused by a tax may results in earning burdens of the both parties of transaction; and income decrease, which is traditionally regarded as tax burden in the theory of indirect taxation, is just one aspect of earning burdens. 我が国の消費税制度は、納税義務を負う売り手が税額を価格に上乗せして販売することで売り手に税負担を転嫁し、その税負担は最終的に全て消費者のものとなることを予定している。間接税の理論では通常、課税による値上がり分を買い手が引き受けると見なす。しかし領収書等に記される消費税分の額は単に価格の8/108（税率8%の場合）を示したものであり、必ずしも課税による値上がり分ではない。このため個々の取引において売り手から買い手に転嫁されている税額ははっきりしない。税は国民の財産権に関する制限であり、税負担の額が明らかでないことは人権の観点から問題である。 筆者らはこの問題に対して既に、法的負担と稼得負担という尺度概念を提案し、それらを用いて消費税の負担を整理する予備的な議論を一般向けに行った。本稿ではより学術的かつ精確にそれらの尺度の意味付けを試みる。法的負担とは私的経済主体が課税によって自らの所有から財産を政府に移転させられるという負担を表す。稼得負担とは私的経済主体が市場から金銭を稼ぐために代償（努力など）を払うという負担を表す。消費税の負担についてこれらの尺度を用いて検討することにより、法的負担は売買において取引相手に転嫁されることはなく、納税義務を負う売り手が正確に税額を負担する税であること、また課税による価格の変化は当事者に稼得負担を引き起こすことがあり、間接税の理論で負担と見なされる所得の減少はその一面であることを示す。