A cell observation system includes an imaging element that acquires images of the inside of a culture container in which cells are cultured, the imaging element acquiring the images over time; a computer configured to: quantitatively analyze a culture state of the cells cultured in the culture container on the basis of each of the images acquired by the imaging element; and statistically analyze the quantitatively analyzed data; and a display that displays statistical analysis results in the culture container within a plurality of subculture periods obtained by the computer in a manner allowing comparison of the statistical analysis results.