1. A body-movement detecting apparatus comprising: an acceleration sensor configured to be mounted on a body of a user; vertical-component extracting means for extracting a vertical component of an acceleration from a detection output from the acceleration sensor; separating means for performing component separation of the vertical component extracted by the vertical-component extracting means into a high-band component and a low-band component; detecting means for detecting a peak-position candidate on the basis of the low-band component of the vertical component separated by the separating means; identifying means for identifying the peak-position candidate detected by the detecting means as a peak-position candidate in a case where a ratio between energy of the low-band component and energy of the high-band component in a predetermined range including the peak-position candidate is less than a predetermined value; and body-movement detecting means for detecting body movement of the user on the basis of the peak-position candidate identified by the identifying means, said body-movement detecting means counting a number of peak-position position candidates to determine a number of body movements of the user.