Abstract: A shift drive mechanism for a multi-speed transmission in which a shift rod can be stably maintained at a desired fixed position without the need for an intermittent drive mechanism and which is small in size and low in cost. The shift drive mechanism for a multi-speed transmission includes a shift guide groove G formed in a shift drum so as to guide a shift pin moved in the axial direction together with the shift rod. Each of gear speed groove portions Gs is formed at axial-direction positions determined on a gear speed basis and directing the shift pin only to the circumferential direction or not moving the shift pin in the axial direction attendant on turning of the shift drum is set to be longer than the distance the shift drum travels idly from the moment of stop of driving of a shift actuator.