A detected signal of a heartbeat sensor (21) and a detected signal of an inertial sensor (22) are received by a processor (31 or 23). The processor estimates a heart rate in a case where an exercise intensity obtain from the detected signal of the inertial sensor (22) is equal to or more than a threshold value, based on a relation between the exercise intensity and a heart rate obtained from the detected signal of the heartbeat sensor (21) during a period in which the exercise intensity obtained from the detected signal of the inertial sensor (22) is less than the threshold value.
