Fuel pump

In a fuel pump (4), two independent seal members (44,45) are disposed to seal a clearance between an inner surface (411a) of a cylinder (411) and an outer surface (412a) of a plunger (412). At least a sliding portion of the seal member (45) with the plunger (412), being closer to a pressure chamber (413) among two seal members (44,45), is made of abrasion resistance material.