Provided is a pain estimating device with which it is possible to estimate objectively and accurately pain being experienced by a subject. A pain estimating device 110 estimates the magnitude of pain being experienced by a subject, on the basis of brain waves of the subject, and is provided with: a measuring unit 111 which acquires a plurality of items of brain wave data or analysis data thereof by measuring brain waves from the subject a plurality of times； and an estimating unit 112 which estimates the relative magnitude of the pain being experienced when the brain wave measurements were conducted a plurality of times, from the plurality of items of brain wave data or the analysis data thereof (for example the amplitude), on the basis of the linearity of a relationship between the brain wave data or the analysis data thereof (for example the amplitude) and the pain. The present invention also provides a pain estimating method and device with which it is possible to estimate objectively and accurately pain being experienced by a subject, and to classify simply the quality and quantity thereof. The present invention also provides a method for generating a pain classification value for classifying pain being experienced by the subject, on the basis of brain waves of the subject.L'invention concerne un dispositif d'estimation de la douleur qui permet d'estimer objectivement et avec précision la douleur ressentie par un sujet. Sur la base des ondes cérébrales émanant du sujet, le dispositif d'estimation de la douleur 110 selon l'invention estime l'amplitude de la douleur ressentie par ledit sujet, et comprend : une unité de mesure 111 qui acquiert une pluralité d'éléments de données d'ondes cérébrales ou de données d'analyse de celles-ci par mesure des ondes cérébrales émanant du sujet une pluralité de fois ； et une unité d'estimation 112 qui estime l'amplitude relative de la douleur ressentie quand les mesures d'ondes cérébrales ont été effectuées une pluralité de foi
