According to the custom of Taiwan, rotating savings and credit association (RSCA hereinafter) can be categorized into two types of contract: the single-line module and the multi-line module. Before the customs of RSCA was codified, most of the court rulings were based on the precedents of the Supreme Court which lately recognized the single-line module as the only way RSCA operated. When the custom of RSCA was codified in May 2000, by contrast, the multi-line module was adopted as the primary framework of civil law amendment. Through the analysis of court cases collected from Taichung District Court and Taichung Branch of High Court, it is found that the autonomy of private law is violated by the existing civil law with reference to RSCA. Moreover, the Civil Code provides less protection for the leader of the association than the members not winning the bid in cases where the members who have won the bid fail to deliver the payments in the following paragraphs. Suggestions for the amendment of Civil Code are provided in this article.