Provided is a spectrophotometer using medium energy ion. The spectrophotometer using medium energy ion is configured to include: an ion source 10 generating ions; a collimator 20 collimating the ions as a parallel beam; an accelerator 30 accelerating the parallel beam; an ion beam pulse generator 40 pulsing the accelerated ion beam; a focusing objective 50 focusing the pulsed ion beam on a specimen 1; a detector 60 detecting a spectroscopic signal of scattered ion from a specimen 1; and a data analyzer 70 analyzing and processing the spectroscopic signal detected by the detector 60.