A tappet is used in a valve-operating mechanism of an internal combustion engine. The tappet has a top wall and the upper surface of the top wall is engaged with a cam. The lower surface is engaged on a poppet valve which moves up and down. A downward projection which has a recess for storing lubricating oil is formed in the middle of the lower surface of the top wall of the tappet, thereby lubricating interfaces with the cam or valve to improve frictional or wear resistance.