To provide a common rail type fuel injection device having a large pulsation-reducing effect of the inlet pressure of an injector by avoiding deterioration in productivity.

A flow damper 31 fastened to a rail body 20 is formed so that a piston upstream side orifice 61 is arranged in a cap 35 installed on the fuel upstream side of a valve body 32, and a piston downstream side orifice 62 is formed in a press-in member 63 pressed in an upper fuel passage 46 on the fuel downstream side of a piston 33. Thus, the movement of the piston 33 is blunted by restraining a volumetric variation on the upstream-downstream side of the piston 33, and pulsation generated in the injection of the injector is reduced by the piston downstream side orifice 62, and does not directly affect the piston 33, and the pulsation of the inlet pressure of the injector can be reduced. Since there is no need to extremely reduce an orifice diameter, the deterioration in productivity is not caused.