The present invention relates to an acceleration measuring device capable of acquiring the offset for correcting the output of a triaxial acceleration sensor. The invention is provided with an acceleration sensor for detecting the acceleration in a triaxial direction, a data acquisition portion for acquiring the triaxial output data, a data selecting portion for judging whether repeatedly acquired triaxial output data are appropriate to make a selection, a data accumulating portion for accumulating the thus selected triaxial output data, a reference point estimating portion estimating coordinate values of the reference point determined in the three-dimensional cartesian space by referring to the distribution of a predetermined number of accumulated triaxial output data in a three-dimensional cartesian space when each axial component is given as a coordinate value, and an offset correction/calculation portion for correcting the offset of the triaxial output data of the acceleration sensor.