A high-pressure oil pump roller tappet, used for automobile fuel injection system, mounted between the driving cam and the tappet. The roller tappet includes a shell, a holder, a roller, and a pin. Planes A are arranged on both sides of the seam on lateral sides of the shell. Holes I are arranged at symmetrical positions on two planes A. Holes II are arranged on symmetrical positions on vertical plates. The roller is located in the middle of the pin. Welding has no requirement on the thickness of the plate. The weight can be controlled effectively, reducing inertia force, friction, and wear, improving engine efficiency. The shell and holder are designed as being separate, ensuring that the shell subjects to lateral force as little as possible when the holder subjects to a force, such that the shell is less likely to vibrate. Thus, the shell avoids the abrasion.