PROBLEM TO BE SOLVED: To provide a heartbeat measuring apparatus capable of tightening the chest by appropriate strength with a belt during exercise by simple operation and, simultaneously starting and terminating measuring and recording operations of the heart rate, and an operation method thereof.SOLUTION: In a heartbeat measuring apparatus 1, at a position where connection bars 12A and 12B come into contact with locking pins 13a and stop, the other ends (both ends of a belt) of the connection bars 12A and 12B come close to each other, a belt 20 is set to a tightening state, and a power supply of a measuring part 10 is set to an on state. However, at a position where the connection bars 12A and 12B come into contact with the locking pins 13b and stop, the other ends (both ends of the belt) of the connection bars 12A and 12B are separated from each other by prescribed distance, the belt 20 is set to a tightening-released state, and the power supply of the measuring part 10 is set to an off state.
