PROBLEM TO BE SOLVED: To provide an aquatic organism observation system with alighting device capable of smoothly executing a visual inspection which is a simple analytical item of a ballast water sampling at the time of ship inspection.SOLUTION: An aquatic organism observation system with a luminaire is constituted by a visual inspection device and a lighting device. The visual inspection device has an effective volume of 0.1 L to 3.0 L, and includes a square three-dimensional shape transparent water tank having a front face, a rear face, a bottom face, and two side faces. The luminaire includes a light source 4 for applying LED light to a visual inspection object water, and irradiates the LED light to ballast water inside the transparent water tank by collecting, into the transparent water tank, a predetermined volume of the ballast water inside a ship which is visual inspection object water, and counts the number of aquatic organisms by making visibility of the aquatic organism in the ballast water obvious
