1. A subject person specifying apparatus comprising: a processor, and a memory storing a program causing the processor to execute: acquiring characteristic quantities of variations of heart rate related to a meal of a subject person from heart rate data of the subject person as a target of an individual specifying process; calculating a distribution range of history values of the characteristic quantities associated with a plurality of candidates; and extracting the candidate corresponding to the subject person from within the plurality of candidates, based on a relation between the characteristic quantities acquired from the subject person and the distribution range of the history values of the characteristic quantities.