A mirror device includes a frame body, a mirror configured to tilt about a Y-axis with respect to the frame body, a fixed inner comb electrode including a plurality of electrode fingers arranged in the arrangement direction along the Y-axis and provided at the frame body, and a movable inner comb electrode including a plurality of electrode fingers arranged in the arrangement direction and provided at the mirror, the electrodes fingers of the fixed inner comb electrode and the movable inner comb electrode being alternately arranged. The mirror includes a mirror body and an extension extending from the mirror body. Some of the electrode fingers of the movable inner comb electrode are provided at the mirror body, and another electrode fingers of the movable inner comb electrode are provided at the extension.