PROBLEM TO BE SOLVED: To provide a protection member for a reaping blade of a mobile mowing machine in which the resistance of trees and plants are reduced, and the mowing machine can smoothly be operated with superior workability, even if the protection member for protecting the reaping blade is moved during mowing work.SOLUTION: A protection member 5 is mounted on a mobile mowing machine in which a reaping blade 3 provided on the tip of an operation rod 2 is rotated by a motor to reap grass, and protects the reaping blade 3. The protection member 5 comprises at least a peripheral ring 51, a mounting board 52 positioned on the same core of the ring and having a mounting hole in the center, and multiple connecting bars 53 for radially connecting between the peripheral ring 51 and the mounting board 52. Also, the mounting board 52 is positioned on the upper part of the peripheral ring 51 and connected by the connecting bars 53.