The thermal collector tube of the invention is a thermal collector tube used in concentrated solar power generation, in which solar light is collected using reflecting mirrors, the collected light is converted into heat using a thermal collector having the thermal collector tube, and power is generated using the heat, in which the thermal collector tube has a main body portion that houses the heat medium, and a coating layer which is formed on the outer surface of the main body portion, and has a radiation rate of 0.70 to 0.98 at room temperature and a wavelength of 1 µm to 15 µm.