Abstract: The present invention provides a heart-rate variability analysis method and analysis device that have a 24 hour monitoring function, that have a function for the high-precision measuring of the R-R interval heart-rate, and that can exclude the effect of respiratory movement on heart-rate variability. The present invention also provides a heart-rate variability analysis device capable of performing a detailed analysis of the heart rate. The heart-rate variability analysis device comprises a measurement portion (1) and an analysis display portion (2). The measurement portion (1) has first and second cardiac action potential measuring means (11), (12) that are attached to the thoracic region and the diaphragmatic region, respectively; three-axis acceleration measuring means (13), (14); and transmitters (15), (16) for transmitting the measured cardiac action potential signals and acceleration signal to the analysis display portion (2).