To provide a rotation drive transmission device capable of absorbing torsional vibration caused by the torque fluctuation of an engine by connecting a connecting block fixed to an outer shell of a torque converter, a starting device, etc., and a connecting plate mounted to the tip of an crankshaft of the engine with a stopper.

The connecting plate 8 mounted to the tip of the crankshaft 7 of the engine is connected and fixed to the connecting blocks 9, 9 ..., fixed to the outer periphery of a front cover. Furthermore, dynamic vibration absorbers 15, 15 ..., are attached within a space between the connecting blocks, a disk-like weight 17 is stored in the dynamic vibration absorber 15, and the disk-like weight 17 is moved in a curved groove 16 according to a change in the rotational speed due to the torque fluctuation of the engine so as to absorb the torsional vibration.