A mechanical valve lifter for an internal combustion engine comprises a head section having a recessed portion on an upper face thereof, a skirt section formed integral with the head section and adapted to be in sliding-contact with a lifter guiding bore in an engine cylinder head, a mechanical valve-clearance adjusting shim put in the recessed portion, an annular groove formed in an upper face of a bottom wall of the recessed portion of the lifter body, a first through-opening formed in the shim to communicate with the annular groove, and a second through-opening formed in the head section to communicate with the annular groove and to penetrate the head section. The annular groove and the second through-opening are formed in an essentially zero bending moment area midway between a central axis of the head section and a peripheral wall of the recessed portion.