A fuel injection system (10) with reduced pressure pulsations in the fuel discharge paths from the injectors is disclosed. A high-pressure fuel accumulated in a common rail is injected by a plurality of the injectors. Each injector includes a high-pressure chamber for accumulating the fuel, a back pressure chamber into which the high-pressure fuel is introduced from the high-pressure chamber and a nozzle body arranged in the high pressure chamber. Each injector closes the fuel injection port by pushing down the nozzle body under the pressure of the high-pressure fuel introduced into the back pressure chamber. The fuel injection port is opened, on the other hand, by discharging the high-pressure fuel from the back pressure chamber through the fuel discharge path of each injector. A variable-area orifice (6) is arranged in the discharge path (55) downstream of the confluence at which all the fuel discharge paths from the injectors are merged with each other. The higher the fuel pressure in the discharge paths, the larger the open area of the variable-area orifice. Thus, a pressure pulsation in the fuel discharge paths from the injectors is reduced.