Provided is a hydrogenation annealing method using a microwave, which performs hydrogenation annealing at a low temperature and with low power in a manufacturing process of a thin film transistor (TFT) for a display device. The hydrogenation annealing method is constituted by a loading step of loading a device requiring hydrogenation annealing into a chamber and an annealing step of irradiating a microwave having a frequency in an industrial scientific medical (ISM) band into the chamber into which the device is loaded. As hydrogenation annealing is performed at a low temperature by using the microwave for an oxide semiconductor TFT or LTPS having very large electron mobility, high integrated energy is transmitted to the device by the microwave, thereby implementing recoupling of hydrogen atoms which have been performed only at a high temperature, even at a low temperature.