In considering the inherent nature of taxation, there are certain items that should not be taxed such as interest income, proceeds from the sale or leasing of land (including leaseholds) or proceeds from the sale of commodity vouchers (merchandise coupons, beer coupons). Also, there are certain business activities considered unsuitable for taxation from a public policy perspective such as the income of doctors derived from social insurance medical fees. These are excluded from taxable sales and labeled as "non-taxable transactions"

税の性格からみて課税対象になじまないもの（受取利息、土地（借地権等を含む）の売却代金・賃貸収入、物品切手等（商品券、ビール券等）の販売代金など）や、社会政策的な配慮から課税することが適当でない取引（医師の社会保険診療収入など）は課税売上げから除かれます。これらを非課税取引といいます。

However, interest and discount fees, insurance premiums and the purchase or lease of land are non-taxable transactions and therefore not classified as taxable purchases. The payment of salaries and wages not subject to tax is also excluded from taxable purchases.

ただし、利子割引料及び保険料等の支払、また、土地の購入や賃借等は非課税取引ですので、課税仕入れとはなりません。課税対象とならない給与、賃金の支払等も課税仕入れに含まれません。