The utility model provides a switch cabinet dehumidifying apparatus, switch cabinet dehumidifying apparatus set up in the cubical switchboard outsidely, switch cabinet dehumidifying apparatus includeair compressor machine, desicator, intercommunication desicator and cubical switchboard the intake pipe and with the cubical switchboard intercommunication and with the air escape's in the cubical switchboard outlet duct, the outside air gets into in the air compressor machine dryly through the desicator again, again by with to cubical switchboard inside dehumidification in the intake pipe accessswitch cabinet, is discharged by the outlet duct at last. Through setting up switch cabinet dehumidifying apparatus in the outside of cubical switchboard, break down as switch cabinet dehumidifying apparatus, need not to have a power failure and open the cubical switchboard again, maintain switch cabinet dehumidifying apparatus again, can be directly maintain switch cabinet dehumidifying apparatusin the cubical switchboard outside, so both made things convenient for switch cabinet dehumidifying apparatus's maintenance, and can not maintain because of having a power failure and bring inconvenience and economic loss for the user.