扣繳義務人是受國家委託行使公權力，於給付所得給納稅義務人時，依法扣繳稅款繳納國庫的人。為了促使扣繳義務人克盡職責，所得稅法第114條訂有扣繳義務人違反扣繳義務的處罰規定。所得稅法對於學校的扣繳義務人，規定於第89條第1項第2款，該款規定在88年1月14日修正前，係以學校的主辦會計為扣繳義務人，於修正後改以責應扣繳單位主管為扣繳義務人。其修正的時間，恰好在中山科學研究院發生鉅額稅款未依法扣繳，財政部臺灣省北區國稅局對其主辦會計裁處鉅額罰鍰之後，故該項修正顯然是受到該案的影響。該項修正後雖然給予機關、團體及學校，自由決定扣繳義務人的空間，但這樣的規定是否合憲，值得探討。司法院大法官於99年3月26日作成的673號解釋，對於所得稅法第88條第1項第2款作出合憲的解釋，惟係對於88年1月14日修正前的規定作解釋，並未針對修正後的規定作探討，其原因為何？本文擬就該號解釋的主文及其理由書的推論過程，提出本文的意見。

The tax withholder is the exercise of public power entrusted by the State. When they pay income to the taxpayer, according to Income Tax Law they should withhold taxes and pay to the treasury. To facilitate the withholding of due diligence, Article 114 of the Income Tax Law provides the tax withholder withholding obligation breach penalties. Income tax law for the tax withholder of school, provided for in Article 89, paragraph 1, paragraph 2, which provides before the amendment on January 14, 1999, the chief of the school accounting division is the tax withholder, after the amendment should be responsible for withholding change to the chief in charge by school. The amend time, just a huge taxes withholding breach in Zhongshan Institute, National Tax Bureau of Northern Taiwan Province of Ministry of Finance fine the huge fines, so the amendment is clearly affected by the case. Although the amendment grants institutions, organizations and schools, have the power to designate the tax withholder, but the constitutionality of such provisions should be research. Grand Justices on March 26, 2010, made of Interpretation No. 673, Section 88 of the Income Tax Act, Section 1, paragraph 2, to constitutional interpretation, but Interpretation No. 673 just to explain the requirements before the amendment on January 14, 1999, did not make explanation for the revised amendment, the reason why? This article intends to explain the reasoning process on the Interpretation No. 673 and put forward the views of this article.