the distance l ap up to the leakage position p is calculated the leakage position analysis unit 21 reads out map information corresponding to the geographical position of the leakage position p specifies the manhole etc nearest to the leakage position p prepares a neighboring map including the specified leakage position p manhole and the like plots the leakage position p the manhole nearest to the leakage position p and the like and prepares a leakage position map in which distances from the nearest manhole or the like up to the leakage position p are displayed step s 8 the prepared leakage position map is transmitted as the analysis results to the measurement terminal 1 a by the wireless communication unit 22 step s 9 the measurement terminal 1 a receives the leakage position map from the wireless communication unit 22 step s 10 the control unit 14 of the measurement terminal 1 a displays the leakage position map on the output display unit 16 step s 11 one example of the leakage position map displayed on the output display unit 16 is illustrated in fig8 in fig8 the leakage position p and the manhole nearest to the leakage position p are plotted on a map on which roads and building names are displayed further by confirming the analysis results the examiner can know the manhole to be approached for confirming the leakage.