Vertical-component extracting means (2) extracts a vertical component from an acceleration vector corresponding to body movement of a user from a three-axis acceleration sensor (1), and the vertical-component is separated by a high-band/low-band separating unit (3) into a high-band component and a low-band component. Using these components, a peak detection/determination processing unit (4) 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 (5) detects a body-movement pitch. Accordingly, without being affected by various types of noise, it becomes possible to accurately detect body movement of the user in the vertical direction, and also to accurately detect the body-movement pitch of the user as needed.
