A MEMS sensor includes a first substrate; a second substrate; a movable electrode portion and a fixed electrode portion which are arranged between the first substrate and the second substrate, wherein: conductive supporting portions of the movable electrode portion and the fixed electrode portion are, respectively, fixedly secured to a surface of the first substrate via a first insulating layer; a second insulating layer, a lead layer buried into the second insulating layer, and connection electrode portions that are electrically connected to the lead layer to be individually connected to the conductive supporting portions are provided on a surface of the second substrate; a metallic connection layer is formed on the surface of one of the respective conductive supporting portions; one of the respective connection electrode portions and the metallic connection layer are bonded together by eutectic bonding or diffusion bonding; and, at least each of the connection electrode portions has a thickness of about 4 μm or smaller.