The present invention relates to an auxiliary wheel for a lawn mower which includes an installation unit coupled to a main body of a lawn mower, a swing unit coupled to the installation unit to be swingable in one direction or the other direction, a wheel unit connected to the swing unit to be swingable with the swing unit, and a fixing unit installed on an outer portion of the installation unit and configured to fix the swing unit to be swingable in the other direction. When the wheel unit swings in the one direction, the main body is pressed against the ground, and when the wheel unit swings in the other direction, the main body is spaced apart from the ground.