Micro-electromechanical device for measuring the viscosity of a fluid, comprises a measuring chamber with a micromechanical actuator, arranged as a cantilever above a metallically conductive counter electrode, elastically deformable towards the counter electrode, surrounded by the fluid to be measured and made of a metallically conductive material, a two-terminal RF voltage source that can be switched off, having a first output terminal connected to the actuator, and a second output terminal connected to the counter electrode, and which is designed to output an RF voltage signal that is suitable for deflecting the actuator out of its rest position, and a measuring device to detect a change in the frequency, amplitude or phase of the RF signal in order to determine a measurement value for the viscosity-dependent speed at which the actuator is deformed.