An apparatus for measuring a bioelectrical impedance, the apparatus comprising: a first electrode; a second electrode; a third electrode; a fourth electrode; a current source configured to apply a constant current to an object through the first electrode and the second electrode; a measurement mode switcher configured to switch a measurement mode from a first measurement mode to a second measurement mode in response to a measurement mode switch signal, wherein a four-point impedance measurement method is used in the first measurement mode, and a two-point impedance measurement method is used in the second measurement mode; a voltmeter configured to obtain a voltage applied to the third electrode and the fourth electrode due to the constant current applied to the object through the first electrode and the second electrode, in the first measurement mode and the second measurement mode, respectively; the apparatus being characterized in that it comprises a processor configured to determine a time point t1 at which a first impedance of the first measurement mode obtained based on a first voltage exceeds a predetermined first threshold, wherein the predetermined first threshold is set in consideration of a dynamic range of the apparatus for measuring the bioelectrical impedance, generate the measurement mode switch signal at the time point t1, obtain the first impedance based on the first voltage obtained by the voltmeter at time point t1, monitor a measurement impedance based on the voltage obtained by the voltmeter after the start of the measurement mode switch from the first measurement mode to the second measurement mode, determine a time point at which a change of the measurement impedance turns from positive (+) to negative (-) as a time point t2 of the completion of the measurement mode switch from the first measurement mode to the second measurement mode, obtain a second impedance based on a second voltage obtained by the voltmeter at the time point t2, and obtain a bioelectrical impedance of the object based on the first impedance and the second impedance. a first electrode; a second electrode; a third electrode; a fourth electrode; a current source configured to apply a constant current to an object through the first electrode and the second electrode; a measurement mode switcher configured to switch a measurement mode from a first measurement mode to a second measurement mode in response to a measurement mode switch signal, wherein a four-point impedance measurement method is used in the first measurement mode, and a two-point impedance measurement method is used in the second measurement mode; a voltmeter configured to obtain a voltage applied to the third electrode and the fourth electrode due to the constant current applied to the object through the first electrode and the second electrode, in the first measurement mode and the second measurement mode, respectively; the apparatus being characterized in that it comprises a processor configured to determine a time point t1 at which a first impedance of the first measurement mode obtained based on a first voltage exceeds a predetermined first threshold, wherein the predetermined first threshold is set in consideration of a dynamic range of the apparatus for measuring the bioelectrical impedance, generate the measurement mode switch signal at the time point t1, obtain the first impedance based on the first voltage obtained by the voltmeter at time point t1, monitor a measurement impedance based on the voltage obtained by the voltmeter after the start of the measurement mode switch from the first measurement mode to the second measurement mode, determine a time point at which a change of the measurement impedance turns from positive (+) to negative (-) as a time point t2 of the completion of the measurement mode switch from the first measurement mode to the second measurement mode, obtain a second impedance based on a second voltage obtained by the voltmeter at the time point t2, and obtain a bioelectrical impedance of the object based on the first impedance and the second impedance.