1. A discrimination filtering device comprising: a first filter with a first pass band based on a spectrum for a plurality of types of specimens whose classification is identified in advance, the first pass band adapted to lower the probability of a specimen belonging to a group being erroneously determined as belonging to another group, a second filter with a second pass band encompassing said first pass band, a detection unit for detecting an electromagnetic wave output from an object of interest and passed through one of said first filter and said second filter to output a first signal and a second signal corresponding to intensity of the electromagnetic wave from said object of interest, and an analysis unit for performing a discriminant analysis of said object of interest based on said first signal normalized by an integral of said second signal.