Provided are an optical system for analyzing multi-channel samples which uses a mirror rotating at high speeds and an aspherical mirror, and a multi-channel sample analyzer employing the optical system. The optical system for analyzing multi-channel samples, includes a light source unit which emits light traveling along an optical axis; a semi-spheroid aspherical mirror disposed in rotational symmetry about the optical axis; and an inclined mirror which reflects the light exiting the light source unit to the semi-spheroid aspherical mirror, while rotating about the optical axis, wherein an opening is formed in the center of the semi-spheroid aspherical mirror such that the light exiting the light source unit enters the inclined mirror through the semi-spheroid aspherical mirror.