To provide a device for protecting the optical instrument of an artificial satellite having a sufficient rigidity capable of controlling the satellite.

The device for protecting the optical instrument of the artificial satellite includes a body for loading the optical instrument. The protection device takes a folded position and a deployed position and is provided with a plurality of rigid panels 202, 203 in the deployed position. A pipe is formed so as to have a polygonal cross section arranged so that the device protects the optical instrument. The longitudinal axis of the pipe is substantially parallel with the focal axis of the optical instrument. The device is formed by the panels 202, 203 at the position where a plurality of faces of the pipe having the polygonal cross section are folded. The panels 202, 203 are held against the body of the satellite.