An electronic vehicle horn outputs a warning sound by exciting a diaphragm using a piezoelectric device that is driven with a composite signal generated, in part, by modulating a first fundamental square wave with a first modulating square wave and setting a frequency deviation at the time of the modulation in a predetermined range, modulating a second fundamental square wave with a second modulating square wave and setting a frequency deviation at the time of the modulation in a predetermined range, and generating the composite signal by mixing the modulated first fundamental square wave and the modulated second fundamental square wave.