Experiments and numerical simulations were performed to study heat transfer through a contact interface between two metallic solids in order to clarify the effects of roughness and waviness of the contact surface on the mean thermal contact conductance h m . In the experiments, the characteristics of an ultrasonic transmission were also investigated so as to obtain a relation between h m and the transmitted sound energy ratio, with and without attenuation, at the contact interface E r . Ten pairs of brass specimens were tested in an atmospheric environment at room temperature. Each specimen was a cylindrical block 40 mm in diameter and 45 mm long. The contact surface was finished by polishing, grinding, milling, or turning. Mean nominal contact pressures p m from 0.08 to 1.67 MPa were applied to the test columns. Our analysis takes account of the radial distribution of thermal contact conductance, using numerical solutions of the two-dimensional cylindrical heat conduction equation to simulate the heat transfer experiments. From the simulations, the effects of roughness and waviness on the temperature fields around the contact surfaces and on h m were clarified. Finally, for flat rough surfaces, an empirical correlation expression between h m and E r is proposed. Using this expression, h m can be predicted to within about ±50%.