Musical factors, such as short melodies or chords, are widely used for various kinds of auditory signals, in addition to intermittent patterns of sounds. In this study, to show the effect of using chords for auditory signals, the relationship between types of triads (three-note chords) and functional imagery and impression of auditory signals was examined by rating experiments. The experimental results showed the possibility of use of the progression from dominant to tonic chord or their base tone progression as a message of ending. The progression from subdominant to tonic chord also could be used for the message of ending. These sounds also aroused impression of pleasantness and brightness. They are appropriate for auditory signals frequently heard in dairy life. Diminished and minor triad was appropriate for informing danger alarm. They aroused impression of unpleasantness and darkness. Augment triad aroused strong imagery of calling. It also could be used for attracting attention. The present study showed using chords is effective to arouse particular functional imageries and impressions.