PROBLEM TO BE SOLVED: To reduce false recognition further that a user is a guest who is not a registered user.SOLUTION: A body weight and biological impedance (BI) are measured, are stored as history data of a measurement result for each of registered users, are compared with past measurement history with respect to the measurement result, history is examined where difference in biological impedance and difference in body weight are within a prescribed allowable range, and a registered user who is largest in history number within both of the allowable ranges is recognized as a measurer of this time. When there is no history within both of the allowable ranges, a user is recognized as an unregistered measurer, that is, a guest. In the embodiment, an allowable range with respect to both differences in the current measurement value and history (biological impedance and body weight) is made larger in identification processing of a measurer in the case that the number of registered users is 1 than in the case of more than one.
