A microelectromechanical element of a hydrophobic surface structure with a long life and high reliability and an electromechanical switch using the microelectromechanical element are provided. The surface of an electrode has a composite surface structure of a first area made of a first material forming the electrode and a second area made of a second material at least having hydrophobicity. The surface structure is the composite surface structure of the electrode material and a monolayer, whereby physical compression of the monolayer is avoided. A structure wherein the monolayer is not formed on the propagation path of a radio frequency signal is adopted, so that an increase in an insertion loss and electric field damage are avoided.