The present invention includes a shell, a light emitter, a beam splitter, a convergent lens, an optical filter, a collimation unit, a discrete light detection unit, and a processing unit. The shell includes a sample well to contain a sample. The light emitter generates a detection beam towards the beam splitter, the detection beam is reflected by the beam splitter before being converged by the convergent lens onto the sample, and a Raman scattered beam is scattered from the sample. The Raman scattered beam respectively passes through the convergent lens, the beam splitter, the optical filter, and the collimation unit, allowing the collimation unit to collimate the Raman scattered beam into a collimated beam. The discrete light detection unit generates multiple light intensity signals according to the collimated beam received, and the processing unit generates a detection result according to the light intensity signals to help detect toxins.