A sound volume controller includes a level adjustment section that adjusts a level of an input audio signal and outputs the adjusted input audio signal as an output audio signal, a level detection section that detects the level of the input audio signal, a volume value detection section that detects a volume value set by a user, a coefficient table storage section that stores a coefficient table which describes a relation between levels of the output audio signal and levels of the input audio signal, a coefficient table change section that changes the coefficient table stored in the coefficient table storage section in accordance with the volume value detected by the volume value detection section, and a setting section that sets an amount of level adjustment of the level adjustment section in accordance with the level of the input audio signal detected by the level detection section and the coefficient table.