There is provided a cell observation apparatus having a sterile chamber 3 containing a culture vessel 1 and a transparent observation window 11 provided in a bottom portion of the sterile chamber 3 and having the culture vessel 1 placed thereabove, wherein the camera 4 and the lighting 5 are provided below the observation window 11. The cells in the culture vessel 1 are imaged through the observation window 11 by setting the focus of the camera 4 to a bottom surface 1d of the culture vessel 1. The lighting 5 emits inspection light L as spot light where the light is not diffused, and an imaging range of the camera 4 is positioned inside an irradiation range of the inspection light L on the bottom surface 1d of the culture vessel 1.