A propeller unit of a marine propulsion apparatus includes: an inner hub; an outer hub arranged coaxially with the inner hub, connected to the inner hub, and provided with a plurality of blades on its outer circumferential surface; and a bushing having a hollow shaft member provided with ribs on an outer circumferential surface and connected to the propeller shaft, and a damper formed of an elastic member and arranged to cover an outer circumferential surface of the hollow shaft member between the outer circumferential surface of the hollow shaft member and the inner circumferential surface of the inner hub, wherein the bushing is spline-coupled to the propeller shaft through spline teeth formed on an inner circumferential surface of a front half or rear half of a longitudinal direction of the hollow shaft member, and has a breakable portion provided in a part corresponding to the non-spline-toothed portion.