Abstract: Provided is a carbon dioxide ground leakage monitoring system that is low cost, capable of real-time multi-point monitoring on a wide scale, and capable of providing the public with easy-to-understand information. A plurality of monitoring posts 100 and a field data server 200 and the field data server 200 and an administrative server 300 are connected by communication lines in respective sections therebetween. The plurality of monitoring posts 100 measure a concentration of carbon dioxide having leaked above the ground, and transmits the measured carbon dioxide data to the field data server 200, the field data server 200 transmits the data transmitted from the plurality of monitoring posts 100 to the administrative server 300, and the administrative server 300 discloses carbon dioxide ground leakage information on the Internet based on the carbon dioxide data transmitted from the field data server 200.