To increase a Q value of resonance, in an MEMS resonator using a vibration mode.

An MEMS resonator 101 comprises: a base material 1 having a flat main surface 1u; an anchor portion 2 fixed on the main surface 1u; and a floating structure 4 fixed to the base material 1 so as to separate from the main surface 1u through the anchor portion 2, and extending from the anchor portion 2 to the side part. The floating structure 4 includes a first trunk portion 41 extending in a first direction 91, and one or more brunch portions 43 extending from an intermediate part of the first trunk portion 41 in a second direction 92 vertical to the first direction 91. The floating structure 4 and the anchor portion 2 are connected through a connecting portion 3 having a cross-section smaller than the floating structure 4 and the anchor portion 2.