Disclosed is a phase change material injection device, which is disposed in a housing or a vehicle headlamp in which a predetermined heat source is provided. The phase change material injection device is configured to eject a phase change material, which has been changed into a gas from liquid by heating of the heat source, into the housing, and may include: i) a container storing the phase change material in a liquid state; ii) a discharge unit disposed at the container for discharging a predetermined amount of the phase change material in a gas state; and iii) a valve unit having an ejection port connecting the discharge unit with the inside of the housing, disposed at the container, the valve unit selectively opening and closing the ejection port based on the internal temperature of the housing.