Abstract: A vertical component is extracted from an acceleration vector corresponding to body movement of a user from a three-axis acceleration sensor, and the vertical-component is separated by a high-band/low-band separating unit into a high-band component and a low-band component. Using these components, a peak detection/determination processing unit detects a peak-position candidate of action of the user in the vertical direction, identifies a peak-position candidate on the basis of an energy ratio between the high-band component and the low-band component, performs waveform matching regarding a predetermined range including each peak-position candidate, thereby determining a peak position, and detects body movement on the basis of the peak position, and a step-position analyzing unit detects a body-movement pitch.