An estimation system comprising: a measurement device measuring a sound signal as a physiology of a subject; an estimation device (AM, 100) estimating a psychiatric disorder of the subject using information on the physiology of the subject which is measured by the measurement device; and an output device outputting a result of the psychiatric disorder estimated by the estimation device (AM, 100), wherein the estimation device (AM, 100) includes: an extraction unit (EU, 10) performing a frequency analysis of the sound signal to obtain information on a fundamental frequency, an intonation and a pitch frequency, wherein the extraction unit (EU, 10) detects regions having the same frequency component from a pattern of a change in intensity in an utterance unit of the sound signal, and acquires a time interval at which the detected regions having the same frequency component appear, as the intonation, extracting an excitement degree as a first information based on a comparison between the obtained intonation and pitch frequency with a predetermined interval and frequency, wherein the excitement degree increases as an interval of appearance in the same frequency component indicated by the intonation becomes shorter than the predetermined interval or as the pitch frequency becomes higher than the predetermined frequency, and extracting an emotion as a second information based on a comparison between the information on the fundamental frequency and a determination tree, wherein the determination tree indicates a relationship between emotions of normal, sorrow, anger, and pleasure and a magnitude, intensity, and average intensity of the fundamental frequency; a calculation unit (CU, 20) obtaining a degree of similarity between changes over time indicated by the first information and the second information being extracted and calculating a shift amount from a predetermined state in which a homeostasis in the subject is maintained based on the degree of similarity being obtained; and an estimation unit (AU, 30) estimating the psychiatric disorder of the subject based on the shift amount being calculated. a measurement device measuring a sound signal as a physiology of a subject; an estimation device (AM, 100) estimating a psychiatric disorder of the subject using information on the physiology of the subject which is measured by the measurement device; and an output device outputting a result of the psychiatric disorder estimated by the estimation device (AM, 100), wherein the estimation device (AM, 100) includes: an extraction unit (EU, 10) performing a frequency analysis of the sound signal to obtain information on a fundamental frequency, an intonation and a pitch frequency, wherein the extraction unit (EU, 10) detects regions having the same frequency component from a pattern of a change in intensity in an utterance unit of the sound signal, and acquires a time interval at which the detected regions having the same frequency component appear, as the intonation, extracting an excitement degree as a first information based on a comparison between the obtained intonation and pitch frequency with a predetermined interval and frequency, wherein the excitement degree increases as an interval of appearance in the same frequency component indicated by the intonation becomes shorter than the predetermined interval or as the pitch frequency becomes higher than the predetermined frequency, and extracting an emotion as a second information based on a comparison between the information on the fundamental frequency and a determination tree, wherein the determination tree indicates a relationship between emotions of normal, sorrow, anger, and pleasure and a magnitude, intensity, and average intensity of the fundamental frequency; an extraction unit (EU, 10) performing a frequency analysis of the sound signal to obtain information on a fundamental frequency, an intonation and a pitch frequency, wherein the extraction unit (EU, 10) detects regions having the same frequency component from a pattern of a change in intensity in an utterance unit of the sound signal, and acquires a time interval at which the detected regions having the same frequency component appear, as the intonation, extracting an excitement degree as a first information based on a comparison between the obtained intonation and pitch frequency with a predetermined interval and frequency, wherein the excitement degree increases as an interval of appearance in the same frequency component indicated by the intonation becomes shorter than the predetermined interval or as the pitch frequency becomes higher than the predetermined frequency, and extracting an emotion as a second information based on a comparison between the information on the fundamental frequency and a determination tree, wherein the determination tree indicates a relationship between emotions of normal, sorrow, anger, and pleasure and a magnitude, intensity, and average intensity of the fundamental frequency; a calculation unit (CU, 20) obtaining a degree of similarity between changes over time indicated by the first information and the second information being extracted and calculating a shift amount from a predetermined state in which a homeostasis in the subject is maintained based on the degree of similarity being obtained; and an estimation unit (AU, 30) estimating the psychiatric disorder of the subject based on the shift amount being calculated.