High Pressure Seal Construction, Method For Machining High Pressure Contact Surface and Fuel Injector

In a high pressure seal for a fuel injector formed by bringing a first contact surface of an injector housing to which a first fuel passage is made to open and a second contact surface of a nozzle body to which a second fuel passage is made to open into pressure contact with each other in a connecting portion of the first and second fuel passages, seal grooves of concentric circle form are applied to at least one of the contact surfaces by finish machining, thereby making it possible to suppress effectively the leakage of high-pressure fuel. The first contact surface and the second contact surface may be formed into concave shapes.