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 brainwaves of the subject, and is provided with: a measurement unit 111 which acquires a plurality of items of brainwave data or analysis data thereof by measuring brainwaves from the subject a plurality of times； and an estimation unit 112 which estimates the relative magnitude of the pain being experienced when the brainwave measurements were conducted a plurality of times, from the plurality of items of brainwave data or the analysis data thereof (for example the amplitude), on the basis of the linearity of a relationship between the brainwave 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 brainwaves of the subject.
