To provide a warning light mounting structure of a window pane for an automobile providing the watertightness of a harness even if a warning light is installed on the outer side of a glass pane.

This warning light mounting structure 10 of a window pane for an automobile has a glass pane 11, a warning light 12 mounted on the outer face 11A of the glass pane 11, a fixing bolt 38 passing through the glass pane 11 and connected to the mounting face 14 of the warning light 12, a harness 39 extending through the glass pane 11 from the warning light 12 and pulled out into the interior of the automobile, and a cylinder part 20 provided on the mounting face 14 of the warning light 12. The cylinder part 20 communicates with a main body and passes through the glass plate to pull the harness 39 out along a hollow part 22 into the interior of the automobile.