We demonstrate a drastic improvement in the efficiency of rare-element-free graphene nanomesh (GNM) magnets with saturation magnetization values as large as ∼10−4 emu/mm2, which are 10–100 times greater than those in previous GNM magnets hydrogenated by only annealing under a hydrogen molecule (H2) atmosphere, even at room temperature. This improvement is realized by a significant increase in the area of the mono-H-terminated pore edges by using hydrogen silsesquioxane resist treatment with electron beam irradiation, which can produce mono-H by detaching H-silicon (Si) bonds. This result must open the door for industrial applications of graphene magnets to rare-element-free magnetic and spintronic systems.