Provided are a somatic data-measuring apparatus that can easily and accurately measure the optimal exercise intensity for the subject being measured, and a somatic data measurement method. The somatic data-measuring apparatus is provided with a heart sound-acquiring means that detects the subject's heart sounds and outputs same as heart sound data, a first heart sound-extracting means that detects the first heart sound on the basis of the heart sound data, a first heart sound amplitude-measuring means that measures the amplitude from the detected first heart sound and outputs same as first heart sound amplitude data, a heart rate-counting means that measures the subject's heart rate and outputs same as heart rate data, and an exercise intensity-computing means that computes the double product of the heart rate data and the first heart sound amplitude data as double product data and detects, as the optimal exercise intensity, the exercise intensity at which the approximation line, which approximates said double product data distribution, bends. Since the double product, which represents myocardial oxygen consumption, is effective as an index that accurately reflects the state of cardiac workload, it is possible to measure accurately the degree of workload on the heart.
