The mini-spectrometer FT (flat type) series is a polychromator provided in a compact, thin case that houses optical elements, image sensor, and driver circuit. Spectrum data can be acquired by guiding measurement light into a mini-spectrometer through an optical fiber and transferring the measured results to a PC via the USB connection. The incorporation of a high-sensitivity CMOS image sensor maintains high sensitivity equivalent to that of a CCD and achieves low power consumption. Moreover, the trigger function that can be used for short-term integration enables spectroscopic measurement of pulse emissions. The product includes evaluation software with functions for setting measurement conditions, acquiring and saving data, draw-ing graphs, and so on. Furthermore, the DLL function specifications are disclosed, so users can create their original measurement software programs.