A micromechanical mirror device has: a plate-shaped mirror having a reflecting surface for reflecting light, the reflecting surface being configured to be planar; a closed frame structure supporting the plate-shaped mirror and completely framing an edge of the plate-shaped mirror; a spring arrangement having at least two spring structures arranged mirror-symmetrically and connecting the closed frame structure to a stationary support structure, the spring arrangement being configured such that the closed frame structure and the plate-shaped mirror can be brought into a resonant vibrational state with respect to the support structure; and a connecting arrangement having at least four connecting spring structures arranged mirror-symmetrically and each connecting the plate-shaped mirror to the closed frame structure; the connecting spring structures being configured to be elastically deformable and arranged such that they deform back and forth in the resonant vibrational state so that the plate-shaped mirror is partially mechanically decoupled from the closed frame structure.