A heat treatment method of a component for a vehicle includes: heating an inner space of a heat treatment furnace in which a component for a vehicle is disposed in the inner space; stabilizing hydrogen (H2) by injecting the H2 into the inner space; and performing nitrification heat treatment for the component by injecting only ammonia (NH3) into the inner space after the stabilizing. The heat treatment method may adjust the degree of vacuum and the flow rate instead of a Kn without additionally injecting the H2 gas into an NH3 gas, thereby implementing the nitrification heat treatment of a quality similar to that of a conventional nitrification heat treatment for a short time.