A pet body fat measuring tool and method for measuring pet body fat by measuring a bioelectrical impedance includes an electrode body including at least two current electrodes and at least two voltage electrodes. The electrode body is pressed to a part of a pet body. The tool also includes a control calculating unit having an impedance measuring circuit connected to the electrode body to control a current made to flow at a time of measurement. The control calculating unit includes, in advance of the measurement, a direct correlation between a body fat percentage of a pet body and the bioelectrical impedance of the pet body to calculate the body fat percentage based on only a bioelectrical impedance determined from measured voltages. A distance between each of the current electrodes and each of the voltage electrode is fixed.
