An information processing device comprising: position information of a plurality of loudspeakers; means for obtaining a target sound image to be moved comprising a sound image position of a sound source including a position in a horizontal direction, a detection unit (92; 133, 136) configured to detect at least one mesh (TR21, TR22, TR23) of meshes, wherein a mesh is a region (AR11; TR 11, TR21, TR22, TR23) surrounded by three loudspeakers placed on a spherical surface (TR11, TR21, TR22, TR23) or an arc between two loudspeakers, and specify at least one mesh boundary line that is a movement target, wherein a movement target is a mesh boundary line to which the target sound image can get when the target sound image is moved in the vertical direction; a calculation unit (21, 62, 63) configured to calculate a movement position of the target sound image on the specified at least one mesh boundary line that is the movement target, based on positions of two of the loudspeakers present on the specified at least one mesh boundary line that is the movement target, and the horizontal direction position of the target sound image, wherein when the target sound image is outside of all of the meshes, the position in a horizontal direction of the target sound image is fixed and the target sound image is moved in a vertical direction from a vertical direction position of the target sound image to the at least one mesh boundary line that is the movement target in response to calculating the movement position of the target sound image on the specified at least one mesh boundary line; and a gain calculation unit configured to, when it is determined that it is necessary to move the target sound image, calculate a gain of a sound signal of sound, based on the movement position, and positions of the loudspeakers of the mesh, in a manner that a sound image of the sound is to be localized at the movement position. position information of a plurality of loudspeakers; means for obtaining a target sound image to be moved comprising a sound image position of a sound source including a position in a horizontal direction, a detection unit (92; 133, 136) configured to detect at least one mesh (TR21, TR22, TR23) of meshes, wherein a mesh is a region (AR11; TR 11, TR21, TR22, TR23) surrounded by three loudspeakers placed on a spherical surface (TR11, TR21, TR22, TR23) or an arc between two loudspeakers, and specify at least one mesh boundary line that is a movement target, wherein a movement target is a mesh boundary line to which the target sound image can get when the target sound image is moved in the vertical direction; a calculation unit (21, 62, 63) configured to calculate a movement position of the target sound image on the specified at least one mesh boundary line that is the movement target, based on positions of two of the loudspeakers present on the specified at least one mesh boundary line that is the movement target, and the horizontal direction position of the target sound image, wherein when the target sound image is outside of all of the meshes, the position in a horizontal direction of the target sound image is fixed and the target sound image is moved in a vertical direction from a vertical direction position of the target sound image to the at least one mesh boundary line that is the movement target in response to calculating the movement position of the target sound image on the specified at least one mesh boundary line; and a gain calculation unit configured to, when it is determined that it is necessary to move the target sound image, calculate a gain of a sound signal of sound, based on the movement position, and positions of the loudspeakers of the mesh, in a manner that a sound image of the sound is to be localized at the movement position.