Abstract: An apparatus for implementing a 3-dimensional virtual sound and method thereof are disclosed, in which computational and storage complexity are reduced, in which system stability is secured, and by which the 3-dimensional virtual sound can be implemented in such a mobile platform failing to be equipped with expensive instruments for the implementation of the 3-dimensional sound as a mobile communication terminal and the like. The present invention includes a first step of giving an inter-aural time delay (ITD) to at least one input sound signal, a second step of multiplying output signals of the first step by principal component weight, and a third step of filtering result values of the second step by a plurality of low-order approximated IIR filter models of basis vectors extracted from a head related transfer function (HRTF). The basis vectors, extracted from the head related transfer function database are approximated using balanced model approximation technique.