Cable trench gas monitoring device

The invention relates to a gas monitoring device which is especially suitable for being used in cable trenches and belongs to the technical field of cable trench gas monitoring device structures. Thegas monitoring device comprises a plurality of gas concentration monitoring modules, a communication device, a monitoring terminal and gas exchanging devices arranged at inlet and outlet of a cable trench, wherein data is transmitted between the gas concentration monitoring modules and the monitoring terminal through the communication device; each gas concentration monitoring module comprises a methane gas monitoring device, an oxygen concentration monitoring device and a sulfur dioxide gas monitoring device; the communication device comprises a lower computer used for encoding the data and anupper computer used for sending the data to the monitoring terminal. The gas monitoring device is capable of monitoring harmful gases with different densities; the staff does not need to enter the trench for monitoring; the g