Disclosed is a measuring device for obtaining numerical information concerning a substance present in the interstitial subcutaneous fluid, the device being equipped with a sensor unit that outputs signals in accordance with the numerical information concerning the substance and an arithmetic unit (control unit) that receives the signals outputted from the sensor unit and arithmetically processes the signals. The sensor unit is equipped with a sensor, some of which is punctured into the skin. The arithmetic unit (control unit) has been disposed so as to be separate from the sensor unit.
