The present invention provides a fuel injection pump which pressurizes and discharges fuel that is drawn in a low-pressure state, the fuel injection pump including a pump housing having a valve holder in which an inlet valve, an outlet valve, and a relief valve are arranged in an interior and a pump chamber is formed between the inlet valve and the outlet valve and a plunger that pressurizes or depressurizes the pump chamber, in which the relief valve is provided on a downstream side of the outlet valve and is configured as a valve for returning the fuel to an upstream side of the outlet valve, and a portion of a passage on the upstream side of the outlet valve and a passage from the downstream side of the outlet valve to an upstream side of the relief valve are separately formed in a same space in the valve holder. The present invention can reduce the number of components of the fuel injection pump and reduce cost.