A bioelectrical impedance measuring device comprises a first electrode unit and a second electrode unit which are nearly rectangular in shape and have electrodes for measuring a bioelectrical impedance on the top surfaces thereof, and a control circuit unit which incorporates an electric control circuit for measuring a bioelectrical impedance and is detachably attached to the first electrode unit and the second electrode unit via connection terminals. Accordingly, a user can disassemble the device into the control circuit unit, the first electrode unit and the second electrode unit and stack these units and can therefore carry around or store the device easily.