An LPI injector includes an injector body that is supplied with fuel from the upper portion and injects the fuel down, an icing tube of which the upper end is coupled to the lower portion of the injector body and that injects the fuel inside the injector body through a fuel injection channel therein, a valve seat disposed between the injector body and the icing tube and fitted in the lower portion of the injector body, having an injection hole to inject the fuel and a tube-fastening groove fitted on the icing tube around the injection hole, and a ball valve that is seated at the injector body of the valve seat and opens/closes the injection hole.