It has been reported that the mechanical properties of concrete would be severely damaged due to the thermal stress and the high vapor pressure when the concrete is subjected to a high temperature environment over 500 °C especially in the cases of the high strength concrete. However, in the cases of the normal strength concrete subjected to the heating up to 300 °C could be generally used after the fire damage, although the durability of such concrete members has not been clarified enough. In this study, the chloride-induced corrosion of steel in concrete subjected to the heating up to 300 °C was investigated. As a result, it was clarified that when the heating temperature exceeded 100 °C, the increase of the porosity of the heated concrete resulted in the decrease of the compressive strength and that the Cl- penetration into concrete accelerated by the heating over 150 °C resulted in the promotion of the chloride-induced steel corrosion in the heated concrete due to not only the increase of the porosity but also the decrease of the Cl- fixing ability of the concrete.