An audio processing method comprising: setting a size of a virtual sound source; and generating a second audio signal by imparting to a first audio signal a plurality of head-related transfer characteristics, wherein the plurality of head-related transfer characteristics corresponds to respective points (p) within a range that accords with the set size from among a plurality of points (p), with each point (p) having a different position relative to a listening point, setting the range individually for each of a right ear and a left ear; and generating the second audio signal for a right channel by imparting to the first audio signal the plurality of head-related transfer characteristics for the right ear, wherein the plurality of head-related transfer characteristics corresponds to respective points (p) within the range set with regard to the right ear, and generating the second audio signal for a left channel by imparting to the first audio signal the plurality of head-related transfer characteristics for the left ear, wherein the plurality of head-related transfer characteristics corresponds to respective points (p) within the range set with regard to the left ear; wherein the generation of the second audio signal includes: setting the range according to the size of the virtual sound source; synthesizing the plurality of head-related transfer characteristics corresponding to the respective points (p) within the set range to generate a synthesized head-related transfer characteristic; and generating the second audio signal by imparting the synthesized head-related transfer characteristic to the first audio signal; and; wherein the synthesizing of the plurality of head-related transfer characteristics includes weight averaging the plurality of head-related transfer characteristics by using weighted values, characterized in that each of the weighted values is set in accordance with a position of each point (p) within the range, wherein each of the weighted values has a greater value at a point p that is closer to the center of the target range, and a smaller value the closer a point p is to the periphery of the target range. setting a size of a virtual sound source; and generating a second audio signal by imparting to a first audio signal a plurality of head-related transfer characteristics, wherein the plurality of head-related transfer characteristics corresponds to respective points (p) within a range that accords with the set size from among a plurality of points (p), with each point (p) having a different position relative to a listening point, setting the range individually for each of a right ear and a left ear; and generating the second audio signal for a right channel by imparting to the first audio signal the plurality of head-related transfer characteristics for the right ear, wherein the plurality of head-related transfer characteristics corresponds to respective points (p) within the range set with regard to the right ear, and generating the second audio signal for a left channel by imparting to the first audio signal the plurality of head-related transfer characteristics for the left ear, wherein the plurality of head-related transfer characteristics corresponds to respective points (p) within the range set with regard to the left ear; wherein the generation of the second audio signal includes: setting the range according to the size of the virtual sound source; synthesizing the plurality of head-related transfer characteristics corresponding to the respective points (p) within the set range to generate a synthesized head-related transfer characteristic; and generating the second audio signal by imparting the synthesized head-related transfer characteristic to the first audio signal; and; wherein the synthesizing of the plurality of head-related transfer characteristics includes weight averaging the plurality of head-related transfer characteristics by using weighted values, characterized in that each of the weighted values is set in accordance with a position of each point (p) within the range, wherein each of the weighted values has a greater value at a point p that is closer to the center of the target range, and a smaller value the closer a point p is to the periphery of the target range. setting the range according to the size of the virtual sound source; synthesizing the plurality of head-related transfer characteristics corresponding to the respective points (p) within the set range to generate a synthesized head-related transfer characteristic; and generating the second audio signal by imparting the synthesized head-related transfer characteristic to the first audio signal; and; wherein the synthesizing of the plurality of head-related transfer characteristics includes weight averaging the plurality of head-related transfer characteristics by using weighted values, characterized in that each of the weighted values is set in accordance with a position of each point (p) within the range, wherein each of the weighted values has a greater value at a point p that is closer to the center of the target range, and a smaller value the closer a point p is to the periphery of the target range.