A method by which physical properties, including the Young's modulus and thermal conductivity of a ceramic layer of a thermal barrier coating formed on a high-temperature member, are quickly and accurately estimated. A method for estimating a physical property of a ceramic includes a step of calculating the Larson-Miller parameter from the time for which and the temperature at which the ceramic is heated; a step of acquiring the porosity of the ceramic corresponding to the calculated Larson-Miller parameter, based on the calculated Larson-Miller parameter and a diagram correlating the Larson-Miller parameter and the porosity obtained from samples having the same composition as the ceramic; and a step of acquiring the physical property of the ceramic corresponding to the acquired porosity, based on the acquired porosity and a diagram correlating the porosity and the physical property obtained from samples having the same composition as the ceramic.