Sound localization both in the horizontal and the median planes was simulated by the aid of a digital computer through two loudspeakers located in the traverse plane. The simulation was performed by the use of the measured head-related transfer function (HRTF) for two ears. Results of localization tests of three subjects with different sized pinnae show that:(1) When the subject's own HRTF was used in the simulation, natural sound localization in both planes can be performed with the same accuracy as real sound sources.(2) The differences between individual HRTFs affect the accuracy of localization in the simulation. In particular, in the median plane, an HRTF with a high angle-dependency seems to be more advantageous than one with a low angle-dependency.