In this work, the effect of modifying additives of aluminium or boron in the powder of high-speed steel 10R6M5 on the structure and properties of deposited metal by the plasma-powder surfacing is studied experimentally. As established, the inoculation of the deposited metal 10R6М5 with aluminium in the amount of 0.01–0.05% promotes the formation of additional crystallization centres and suppresses the growth of columnar crystallites. As a result, the red hardness of the deposited high-speed steel is increased, and the bending strength and toughness are maintained at the level of forged high-speed steel. The inoculation with boron in the amount of 0.015–0.060% acts on the structure of the deposited metal 10R6M5 similarly to aluminium. However, the formation of Fe$_{2}$B boride, accompanied by an increase in the specific volume by $\cong$ 15–17%, leads to the appearance of significant internal stresses and reduces the bending strength and impact toughness of the deposited metal 10R6М5 modified with boron. An increase in the tool life of a cutting tool made by using plates of deposited metal 10R6M5 modified with aluminium or boron is due to the combination of a fine-grained structure of the deposited metal with a fine carbide mesh and high red hardness.