A tappet (1) for a reciprocating-piston combustion engine, which is situated within a tappet guide of a component fixedly attached to the engine, and having a bearing-mounted roller (8) guided on a pin (3), which roller is in active contact with a cam or an eccentric of a shaft of the reciprocating-piston combustion engine. The casing surface of the cam or eccentric is implemented axially parallel to the shaft and the roller (8) is guided so as to oscillate on the pin (3).