HIGH-PRESSURE FUEL FEED DEVICE

The object of the-present invention is to provide a high-pressure fuel supply apparatus, in which the durability of the fuel sealing section is improved and additionally the evaluation time is reduced. The high-pressure fuel supply apparatus comprises a piston having a plunger supported slidably within a cylinder and a tappet, a casing for preventing the fuel leaking out of the space between the cylinder and the piston from leaking outside by surrounding substantially the cylinder and the piston, and a sealing means for sealing the space between the casing and the piston, wherein the sealing means is fastened to the casing and brought into a slidable contact with the tappet of the piston. The sealing means may either be brought into slidingly contact with the cylindrical surface of the tappet that is fitted in the plunger or be brought into contact with a columnar tappet that simply abuts against one end of the plunger and is supported by the casing in a way in which it can move axially but it does not move radially. The tappet may be made of ceramics.