A measuring cell adapted for a spectral analysis of a gas sample, where this measuring cell is designed and adapted to co-ordinate, from an IR generating element, emitted converging and/or diverging light beams in a direction toward an IR receiving element, by a plurality of reflections of emitted light beams from a number of reflection surfaces assigned to the inner cavity of the measuring cell, thereby creating a predetermined measuring distance in the inner cavity of the measuring cell, from the IR generating element to the IR receiving element. The cavity of the measuring cell is adapted to contain the gas sample intended for a spectroanalytical absorption measurement. Light beams from the IR generating element are, via a reflection surface, convergingly directed to and/or adapted, such as reflectable, in a first reflection surface in order to, when reflected, via a first focal point, as diverging light beams become directed to a second reflection surface, shaped as a concave reflection surface, as well as via third and fourth reflection surfaces become converging to a focal point, in or in the vicinity of the IR receiving element, in order to form a compact measuring cell.