A wiper for an automobile rear-view mirror includes a wiper transmission device installed at the rear side of a rear-view mirror. The wiper transmission device is provided with a transmission motor having a driving gear extending outward to be engaged with a speed-change gear unit for driving a driven gear to rotate. The driven gear is provided with a rotating shaft inserted through the front surface of the rear-view mirror, and the rotating shaft has its outer end fixed with a connecting rod having a wiper fitted thereon. When the transmission motor is started, the wiper can be driven to sway upward or downward for wiping out water drops on the surface of the rear-view mirror to keep the mirror surface clear to enable a driver to clearly watch the traffic conditions reflected in the rear-view mirror and drive with safety.