A valved needle assembly includes a connector having an inner hole, a pipe body fixed to a tip end of the connector, a valve body, and an assembly part in which an insertion part provided to one of the connector and the pipe body is inserted into another such that the connector is disposed within or about the pipe body. A locking protrusion and a locking part are provided to superposed faces of the connector and the pipe body in the assembly part for preventing the insertion part from dislodgment by mutual lock, and an inclined guide surface for guiding the locking protrusion is formed on a tip end in a direction of assembly of the connector or the pipe body to which the locking part is provided. The valve body is incorporated by being mated with the connector and the pipe body.