A detected signal of a heartbeat sensor and a detected signal of an inertial sensor are received by a processor. The processor estimates a heart rate in a case where an exercise intensity obtain from the detected signal of the inertial sensor 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 during a period in which the exercise intensity obtained from the detected signal of the inertial sensor is less than the threshold value.
