An annoyance judgment system includes: a biological signal measurement section configured to measure an electroencephalogram signal of a user a database retaining a plurality of monosyllabic speech sounds such that, for each speech sound, the speech sound and a reference latency of an electroencephalogram negative component corresponding to the speech sound are retained in association a presented-speech sound determination section configured to determine a monosyllabic speech sound to be presented by referring to the database and an annoyance judgment section configured to judge annoyance of the output speech sound by comparing a peak latency of a negative component of the electroencephalogram signal in a range from 50 ms to 350 ms from a starting point, the a starting point being a point in time at which the determined speech sound is presented, against the reference latency corresponding to the determined speech sound that is retained in the database.
