부가가치세법 제17조 특례가 적용된 공급시기와 납부시기에 관한 연구：거래징수제도를 중심으로

[Purpose] This study aims to examine the issue that, under the current Value－Added Tax (VAT) system in Korea, a tax liability arises based on the time of supply even in credit transactions where actual tax collection has not occurred. In particular, Article 17(1) of the Value－Added Tax Act allows suppliers to choose whether to issue a tax invoice in advance, resulting in discrepancies in the time of supply and the point at which the tax obligation is established—even under identical transaction conditions. This study highlights the need to revise the VAT collection and payment system to ensure greater rationality and consistency. [Methodology] Using comparative legal analysis, this study first analyzes the structural and practical differences between the general time－of－supply rule and the special provision under Article 17. Second, it examines the problems in the current tax collection system and finally explores international cases of VAT payment and collection practices to draw insights from cash－based systems. [Findings] The findings indicate that the current legal ambiguity in Article 17(1) causes confusion for taxpayers in determining the tax base and raises the potential for tax disputes. Clarifying the time of supply can enhance legal stability and the predictability of tax obligations while minimizing interpretational conflicts with tax authorities. Furthermore, mandating the issuance of tax invoices at the time of payment, particularly under Article 17(1), would strengthen the effectiveness of the VAT collection system and reduce the risk of tax evasion, thereby improving the reliability and stability of tax administration. [Implications] This study suggests the need to alleviate the rigidity of the existing VAT system, which defines tax liability solely based on the time of supply, and proposes adopting a cash－based VAT system that aligns tax obligations with actual payment receipt. Such reform would improve the fairness of the tax burden, ease liquidity constraints for taxpayers, and enhance the overall predictability and efficiency of the VAT regime.