To provide a quick connector for water system piping capable of being manufactured at low cost and stored in a small arranging space without trouble.

An introducing projection 57 for press fitting is formed in a tube connector 11 of the quick connector for water system piping at one side end in the connector axial direction. A second annular slip stopping projection 59 for press fitting having nearly the same projection height as that of the introducing projection 57 is formed at the other side in the connector axial direction apart from the introducing projection 57 to tightly insert a rubber tube 15 into a tube connector 11.