To solve the following problems in a fuel injection pump loaded on an engine wherein sealability between the outer peripheral surface of a tappet interposed between a plunger compressing fuel in a pressurization chamber and a cam for driving the plunger and the inner peripheral wall of a tappet chamber with the tappet reciprocatingly slid is insufficient, and fuel in the tappet chamber and lubricating oil on the outer peripheral surface of the tappet are mutually mixed to cause blackening of fuel.

In this fuel injection pump, a seal member 19 is provided for sealing a clearance between the inner peripheral wall 17 of the tappet chamber 4 and the outer peripheral surface of the tappet 10. The seal member 19 has such a double seal structure that two different kinds of seal sections, that is, a fuel seal section 191 sealing fuel leaked from the pressurization chamber 15 and a lubricating oil seal section 192 sealing lubricating oil from a cam 11, are separately formed, and the fuel seal section 191 and lubricating oil seal section 192 are juxtaposed through a spacer 193.