A fuel injection pump includes a cam rotating with a camshaft, a cam ring revolving around the camshaft, a housing, plungers for pressurizing and pressure-feeding fuel drawn into fuel pressurizing chambers, and a rotary pump for supplying the fuel to the fuel pressurizing chambers. The housing includes a first housing portion for rotatably housing the rotary pump and second housing portions for housing the plungers so that the plungers can reciprocate. A filter is disposed in one of an outlet portion of a first low-pressure fuel passage in the first housing streaming the fuel from the rotary pump toward the fuel pressurizing chamber, an inlet portion of a second low-pressure fuel passage of the second housing portion facing the outlet portion, and a certain point in the second low-pressure fuel passage.