The present invention relates to a method for manufacturing a transition metal boride powder. The method for manufacturing a transition metal boride powder includes: i) manufacturing a mixed powder by mixing a transition metal halogenide powder and an alkali metal borohydride powder; ii) charging the mixed powder and a plurality of balls into a reaction vessel; iii) charging an inert gas into the reaction vessel and sealing the reaction vessel; iv) high energy ball milling the mixed powder and manufacturing a composite powder containing a transition metal boride and an alkali metal halogenide; v) washing the composite powder in water, dissolving the alkali metal halogenide in the water and filtering the transition metal borides; and vi) drying the filtered transition metal boride and collecting the transition metal boride powder.