New experimental modelling of biomechanical impedance is proposed. The parameters which express the impedance characteristics are simply determined by impedance measurement. Audiofrequencies below about 1000 Hz and comparatively lower preloads (below about 6370 kg m−2) are chosen as the research domain. This model, however, can express wide range of body surface impedance not only in soft but also in stiff and intermediate tissues. It will never introduce the impracticably ideal conditions found in the mathematcial models proposed to date. Furthermore the parameters which express the model cannot be determined by impedance measurement alone. The impedance Z(jw) is expressed in two parts: the impedance Z1 (jw) at a higher frequency including a complex mass and the impedance Z2(jw) at a lower frequency including a complex compliance of Cole-Cole’s type. Z1(jw) is the property of body fluid and Z2(jw) is that of a viscoelastic body.