The present invention relates to an RF MEMS switch device comprising: a substrate; a bias electrode positioned on the substrate and supplying bias voltage; a pair of signal electrodes positioned to be spaced-apart each other on the substrate and transmitting an RF signal from one side to the other side; a dielectric layer formed on upper part of the pair of signal electrodes to be overlapped with the pair of signal electrodes; a membrane electrode formed on the dielectric layer to be overlapped with the pair of signal electrodes and the dielectric layer; a bias line connecting between the membrane electrode and the bias electrode; at least one pooling electrode formed to be overlapped with the membrane electrode and having the dielectric layer be interposed therebetween; and a pooling line connecting any one of the pair of signal electrodes and the pooling electrode, and manufacturing method thereof.