A gear shift operation mechanism capable of achieving reduction in size and weight, reduction in power consumption, simplification and reduction in number of component parts, and cost reduction is provided. A screw shaft that configures a ball screw, a motor that rotates the screw shaft, a nut that is screwed onto the screw shaft, a clutch that is disposed on the screw shaft, and a select lever that is integrated with the screw shaft by switching on the clutch, and has restraint cancelled with respect to the screw shaft by switching off the clutch are included, one end of a main lever is engaged with the nut, the other end is engaged or connected with a shaft, and the select lever is engaged with the main lever.