According to one embodiment, a behavior estimating method for estimating behavior of a person being measured equipped with an activity meter including an acceleration sensor, includes presetting a first angle between a gravitation direction and a direction of action of a standard person being measured, calculating different acceleration waveforms from the activity meter, extracting a second angle between the gravitation direction and the direction of action of the person from the acceleration waveforms, performing a coordinate transformation process among the acceleration waveforms based upon the present first angle and the extracted second angle, and performing behavior estimation of the person using a result of the coordinate transformation.