In order to provide a MEMS resonator having a higher Q factor, by suppressing losses in high-frequency signals due to barriers of thin-film lamination portions, in cases where there exist junction interfaces (barriers), such as pn junctions, in AC-current input/output lines for a vibrator (1) and electrodes (2, 3), the MEMS resonator is structured such that a DC current is flowed therethrough along with an AC current at the same time, in order to reduce resistance losses applied to the AC current, wherein there are provided DC bias circuits (22, 23, 24) for continuously flowing DC currents through the junction interfaces, in an input-electrode side and/or output-electrode side.