An apparatus and method of controlling a temperature of a matching material used in an apparatus for generating a tomographic image is disclosed. The method includes measuring a temperature of a matching material in which an object is immersed in an apparatus for measuring a shape of an object, setting a set temperature at which an amplitude and a phase of an electromagnetic wave that passes through the matching material are maintained, based on the measured temperature of the matching material, and controlling the temperature of the matching material to be higher than the set temperature.