1. An apparatus for specifying a person, comprising: a processor; and a memory configured to store a program causing the processor to execute: acquiring characteristic quantity of variations of heart rate of a subject person related to a meal of the subject person generated from heart rate data of the subject person detected by a sensor and an identifier of the sensor, wherein the characteristic quantity is calculated from the heart rate data obtained for at least one of a first period and a second period, the first period containing a rise of heart rate of the subject person and the second period containing a rise of heart rate of the subject person immediately after the first period; calculating a distribution range of history values of the characteristic quantity associated with a plurality of candidates; extracting one of the plurality of candidates corresponding to the subject person from within the plurality of candidates, based on a relation between the generated characteristic quantity and the distribution range of the history values of the characteristic quantity; and determining whether an identifier of a sensor associated with the one of the plurality of candidates is coincident with the identifier of the sensor or not, and outputting an alert when the identifier of the sensor associated with the one of the plurality of candidates is not coincident with the identifier of the sensor.