A bimodal optical spectroscopy device for producing spectra of autofluorescence and diffuse reflectance signals from a biological sample such as skin. Identified are: an excitation unit including a plurality of monochrome light-emitting diodes and a wideband pulsed lamp; a flexible optical probe including a distally arranged excitation optical fibre, at the centre of the flexible optical probe, to consecutively carry the excitation signals from each element of the excitation unit to the biological sample, and a plurality of distally arranged receiving optical fibres arranged in concentric circles around the excitation optical fibre to carry signals coming from the sample; a detection unit including a plurality of spectrometers, each receiving signals from receiving optical fibres arranged on a single circle in the optical probe; a filter wheel for eliminating excitation signals; and a processing unit for controlling the excitation and detection units and for synchronizing between the units during measurements.