PROBLEM TO BE SOLVED: To provide an estimation method for more accurately estimating a state of a subject than the conventional method.SOLUTION: An estimation method for estimating states of subjects includes: a step (S1) of acquiring brain activity information in time series to be measured in the case of giving a perception stimulus that can correlate to the state to each subject, from respective regions differing from each other in the subject's brain； a step (S3) of calculating, for each subject, a similarity degree group composed of respective degrees of similarity between temporal variations in each of brain activity information obtained from respective regions in the subject's brain and temporal variations in a perception stimulus given to the subject； and a step (S4) of learning correlation between the similarity degree group and the subject's state by using each subject's state that is previously quantized and a similarity degree group corresponding to the subject.SELECTED DRAWING: Figure 1
