When a channel signal, such as a 22.2 channel signal, is rendered into a 5.1 channel signal, a three-dimensional (3D) audio may be reproduced by using a two-dimensional (2D) output channel, however, when an elevation angle of an input channel is different from a standard elevation angle, if elevation rendering parameters according to the standard elevation angle are used, distortion may occur in a sound image. In order to solve the aforementioned problem according to the related art and to prevent front-back confusion due to a surround output channel, an embodiment of the present invention provides a method of rendering an audio signal, the method including receiving a multichannel signal including a plurality of input channels to be converted to a plurality of output channels; adding a preset delay to a frontal height input channel so as to allow each of the plurality of output channels to provide a sound image having an elevation at a reference elevation angle; changing, based on the added delay, an elevation rendering parameter with respect to the frontal height input channel; and preventing front-back confusion by generating, based on the changed elevation rendering parameter, an elevation-rendered surround output channel delayed with respect to the frontal height input channel.