Measurements of subcutaneous fat thickness provide valuable information regarding human health. In previous studies, subcutaneous fat thickness was estimated by bioelectrical impedance; however, this method required sophisticated equipment and analysis. The objective of this study was to develop a simple method to determine subcutaneous fat thickness using apparent resistivity. A single-frequency 50-kHz bipolar pulse was applied to a tetrapolar electrode, while steady-state pulses were used to determine the apparent resistivity. Subcutaneous fat thickness was determined using ultrasound tomography. We obtained a linear correlation of R = 0.916 between subcutaneous fat thickness and apparent resistivity from measurements at 20 sites on a human anterior thigh. The obtained regression equation suggests that subcutaneous fat thickness can be estimated using the apparent resistivity.