A connector that is in a fuel supply system capable of supplying a high-pressure fuel, and may reduce pulsation in a low-pressure pipe with a simple structure and extend the life of a mold is provided. A valve of the connector includes a valve seat contact surface and a tapering through hole. The valve seat contact surface axially separates from an annular valve seat and forms a forward-direction flow path due to pressure of the low-pressure fuel when the high-pressure fuel does not flow in reverse, and may come into contact with the annular valve seat when the high-pressure fuel flows in reverse. The tapering through hole is formed farther radially inward than the valve seat contact surface, forms an orifice flow path having a smaller cross-sectional area than the forward-direction flow path, and allows a reverse flow of the high-pressure fuel when the high-pressure fuel flows in reverse.