The plunger pump according to the present invention discharges fuel by reciprocation of a plunger, and comprises metallic diaphragm type dampers, provided at a fuel inlet side and a fuel outlet side, respectively, for reducing pressure pulsation of fuel. Each metallic diaphragm type damper comprises a pressure chamber for receiving fuel pressure, a back pressure chamber into which gas is charged, and a metallic diaphragm for defining the pressure chamber and the back pressure chamber. Since the metallic diaphragm type dampers are provided at the fuel inlet side and the fuel outlet side, respectively, noise and vibration caused by pressure pulsation are reduced at the fuel inlet side and the fuel outlet side. Also, since the diaphragms are metallic diaphragms, deterioration thereof generated by fuel liquid and back pressure gas is low, reliability is high, and the lifetime is long.