The purpose of the Income Tax Act provision relating to tax exemptions allowed for an individual's combined income tax is to enable the taxpayer to meet his/her legal support obligations, with respect to certain specific relatives or household members, with a tax break. Article 17, Paragraph 1, Subparagraph 1, Item 4, of the same Act stipulates that "the taxpayer, with other relatives or household members, meeting the requirements of Article 1114, Paragraph 4, and Article 1123, Paragraph 3, of the Civil Code, being under twenty years old or sixty years or older without the ability to make a living, and receiving, in fact, support from the taxpayer" may deduct an exemption amount in accordance with the number of people receiving the said support when filing income tax returns. It is a requirement that the taxpayer and persons receiving the support live in the same household. To constitute a household is to live together with the aim of permanently living together. Whether the person receiving support is the taxpayer's head of household or household member, for the purpose of the exemption, shall depend on whether they in fact live together. The fact of whether they are registered under the same household in the household registry shall not be the only determinative factor. Article 21-2 of the Enforcement Rules of the Income Tax Act stipulates that for "the requirement of Article 17, Paragraph 1, Subparagraph 1, Item 4, of this Act, relating to the tax exemptions for supporting relatives/family members, the exemption shall be limited to the taxpayer's other relatives and household members who are listed under the same household registry as the taxpayer or his/her spouse and in fact receive support from the taxpayer." As to the requirement of being "listed under the same household registry" as the taxpayer or his/her spouse, it narrows the applicability of the original law and is in violation of the principle of taxation by law of Article 19 of the Constitution. Any part of the regulation that is inconsistent with the rationales of the above holding shall not be applied.

　　　 Article 19 of the Constitution stipulates that people have the obligation to pay tax in accordance with the law, which means the tax components, i.e., the taxpaying entity, the object being taxed, the tax base, and the tax rates, shall be expressly specified by law. The authorities in charge, in setting the regulations based on the general authorizations from the law, can only regulate matters relating to the enforcement of the original law and should not separately add or eliminate or create taxpaying obligations and requirements. The purpose of the tax exemption provision for an individual's combined income tax in the Income Tax Act is to assist the taxpayer to meet his/her legal support obligation towards certain specific relatives and household members. It is a privilege pertaining to the taxpayer fulfilling such legal support obligation. If the regulation adds or eliminates the exemption requirements without proper legal basis, then it is inconsistent with the principle of taxation by law.

　　　 Article 17, Paragraph 1, Subparagraph 1, Item 4, of the same Act stipulates that "the taxpayer with other relatives or household members, meeting the requirements of Article 1114, Paragraph 4, and Article 1123, Paragraph 3, of the Civil Code, being under twenty years old or sixty years or older without the ability to make a living, and receiving, in fact, support from the taxpayer" may deduct an exemption amount in accordance with the number of people receiving the said support when filing income tax returns. This expressly states that the applicability of the exemption requires that the person being supported, whether a relative or household member, has to in fact receive support from the taxpayer and meet the requirement of Article 1114, Paragraph 4, and Article 1123, Paragraph 3, of the Civil Code, i.e., the requirement of being the head of household or a household member. A household, under the substance over form principle of the Civil Code, is determined by the fact of living together with the aim of permanently living together, and not limited to being registered under the same household registry. Even though Article 4 of the Household Registration Act provides that people living under the same roof are deemed as one registered household, however, at times, head of household and household members living together with the intent to live together permanently may not actually be registered under the same household. For example, a policeman has to register his/her residence at the place of service (Ministry of Finance, April 2, 1980, Interpretative Letter titled Tai-Tsai-Hsu No. 32631). Article 21-2 of the Enforcement Rules of the Income Tax Act stipulates that for "the requirement of Article 17, Paragraph 1, Subparagraph 1, Item 4, of this Act, relating to the tax exemptions for supporting relatives/household members, the exemption shall be limited to the taxpayer's other relatives and household members who are listed under the same household registry as the taxpayer or his/her spouse and in fact receive support from the taxpayer." Its requirement of "listed under the same household registry as the taxpayer or his/her spouse" precludes the taxpayer from proving the person being supported is in fact a household member living together with him/her and narrows the applicability of the original law. It violates the principle of taxation by law of Article 19 of the Constitution, and the said part in violation shall not be applied.