An emotion estimation system includes a memory; and a processor coupled to the memory, wherein the processor executes a process including, acquiring information on one user's heartbeat intervals measured continuously; classifying user's emotion as any one of at least two types of emotions on the basis of a value indicating a ratio of a value obtained as a result of frequency analysis of the acquired heartbeat interval information to a value indicating a gap between a predicted heartbeat interval calculated on the basis of the acquired heartbeat interval information and an actually obtained heartbeat interval; and performing a different output according to a result of the classifying.
EMOTION ESTIMATION SYSTEM, EMOTION ESTIMATION METHOD, AND COMPUTER-READABLE RECORDING MEDIUM