Abstract: An interlocking device for a power transmission operating rod in a power transmission mechanism of a type, wherein the sliding direction of a shift fork shaft intersects with the axial line of the power transmission operating rod, and which is constructed with a supporting frame in the form of a letter "U" fitted at the lower part of a power transmission casing, a guide shaft fixed on the U-shaped supporting frame with the axis thereof being disposed in the same direction as the sliding direction of the shift fork shaft, a shift shaft supported on the guide shaft in a slidable and rotatable manner, a selector having an interlocking mechanism which rotates together with the shift shaft and is rotatably supported on the guide shaft which permits slide-movement of the shift shaft, a selection lever rotatably supported on the U-shaped supporting frame, the one end of which is coupled with the power transmission operating rod and the other end of which is coupled with the selector, and a shift lever rotatably supp