A heart rate of a user is monitored by a heart rate sensor set. On a touch panel, during execution of high-load exercise, time required from the start of the high-load exercise until the heart rate rises to reach a threshold of a lower limit of a target heartbeat zone of the high-load exercise is measured as a first threshold reaching time and displayed in a threshold-reaching-time display section. During execution of the following low-load exercise, time required from the start of the load exercise until the heart rate falls to reach a threshold of an upper limit of a target heartbeat zone of the low-load exercise is measured as a second threshold reaching time and displayed in the threshold-reaching-time display section.
