To simplify a support structure for a valve bridge, and hold stable and smooth valve driving.

This valve drive mechanism for engine causes to simultaneously operates tow valves through a valve bridge 2 by one valve arm 1. Both end push-press surfaces 10a of the valve bridge 2 are mounted on the upper end parts of two valve stems 4 via the receiving tools which are different from respective valve stems 4, and one end push-press part 7 of the valve arm 1 abuts against the center part upper surface of the valve bridge 2, so as to support the valve bridge 2 without a guide rod. In each receiving tool 15, an abutting surface which 15a abuts against the valve bridge 2 is formed into a shape spherical.