To provide a pump control device in which it shows a high responsibility of actual fuel pressure in respect to a desired fuel pressure even in a case that a discharging of fuel from a certain plunger is stopped and an over-shoot of a fuel pressure is prevented.

A pump control device takes a rail pressure (S400), calculates en engine rpm (S402), calculates an injection amount from a fuel injection valve on the basis of the engine rpm and an accelerator opening (S404), and calculates a desired rail pressure (S406). The pump control device calculates an injection pressure feeding ratio except a plunger not discharging fuel (S410) in a case that there is a plunger not discharging fuel while an electric conduction for a rate valve of a fuel supplying pump is stopped (S408:Yes), multiplies the injection pressure feeding ratio in respect to a discharging amount (S414) required for the fuel supply pump calculated under a feed forward control and a feed back control to calculate a command discharge amount in respect to the plunger for discharging the fuel (416).