Originally while amending the Japanese Civil Code, proposals were made to incorporate consumer protection into its system as the general regulations. However, many scholars argued that the Consumer Contract Act, which governs the protection of consumers, has been in place for years, and it was improper to prescribe specific matters in the Civil Code, which serves as a fundamental law. Accordingly, only fundamental regulations, such as mental capacity, mistake in motive, adhesive contract, were amended eventually. Except the large-scale addition of guarantor protection in the Civil Code, the amendment of consumer protection regulations was completed in the Consumer Contract Act. This article will address the division and cooperation for consumer protection under the dual-regulations (i.e. the Civil Code as the fundamental law and the Consumer Contract Act as the special law), and demonstrate how this design prevented the Civil Code from being unenforceable, which was the greatest concern during its amendment.