Abstract: There is provided, in one aspect of the present description, a power transmission apparatus. In one example, the power transmission apparatus comprises, a first driving shaft extending in a first direction, a second driving shaft extending in a second direction, a bevel driving gear arranged on the first driving shaft, and a bevel driven gear arranged on the second driving shaft and meshed with the bevel driving gear. The power transmission apparatus further comprises a fitting shaft formed on the first driving shaft, a fitting hole formed in the bevel driving gear, a contacting surface contacting the first driving shaft so as to restrict movement of the bevel driving gear in a first axial direction, and a snap ring installed so as to restrict movement of the bevel driving gear in a second axial direction that is opposite to the first axial direction.