To provide an optical inspection equipment for fluid having small volume and simple structure.

The optical inspection equipment for fluid comprises a measuring space 8 having a restriction passage 15 for fluid, a monochromatic light source 31 for delivering a light beam F1 to an optical means including a first optical diffraction element 32 having a diffraction grating 38, predetermined as a function of the characteristics of a light source and the geometrical and spectral characteristics, and generating fluorescence toward a fluid, and first, second and third optoelectronic means intended for collecting transmitted light, fluorescence and diffracted light and delivering a signal related to the content of light beam to an analytic unit 24. The light beam is radiated from a second optical diffraction element 42 having a second diffraction grating predetermined as a frequency and geometrical transfer function of the optoelectronic means.