DISCO is an original experimental device devoted to the determination of thermo-optical properties: true temperature, reflectivity and emissivity at high temperature up to 1500°C. It is associated with a 2 kW horizontal axis MSSF for the heating of the sample. An optical fibres probe is moved alternatively in front of the sample and of a reflectivity reference located in the same plane. The emitting and detecting modules of the instrument have two functions: illumination of the instrumented surface using lasers diodes linked with optical fibres, and detection of the emitted and reflected light fluxes using photodiodes associated with monochromatic optical filters and optical fibres. A computer records the measured signals and analyses them to determine the temperature of the sample and its directional reflectivities. An additional optical fibres probe enables to control the in-situ condition (fibres faces pollution, flux losses, ?) of the optical fibres probe used for the measurement.