A cell observation system for observing a cell moving in a flow path with a fluid, comprising: a first observation apparatus including a line camera and a first optical system , the first observation apparatus being configured to capture an image of the cell using the line camera to acquire and output first imaging data; a second observation apparatus including an area camera and a second optical system , the second observation apparatus being configured to capture an image of the cell using the area camera to acquire second imaging data; and a control device configured to analyze the first imaging data output from the first observation apparatus to determine whether the cell satisfies a specific condition, to instruct the area camera to output the second imaging data of the cell determined to satisfy the specific condition, and to analyze the second imaging data output from the second observation apparatus to determine whether the cell is a specific cell; characterized in that the control device is configured to analyze the first imaging data to determine whether there is a cell suspected as a cancer cell, and to analyze the second imaging data to determine whether the cell is a cancer cell, and wherein the area camera comprises a built-in memory of a ring buffer type and is configured to sequentially store the second imaging data at each time point in said built-in memory of a ring buffer type, receive the output instruction from the control device , suspend storing of new second imaging data to the built-in memory when receiving the output instruction, output the second imaging data over a predetermined period of time in the past among the second imaging data stored in the built-in memory at that time, and restart storing of the second imaging data after ending the output of the second imaging data. a first observation apparatus including a line camera and a first optical system , the first observation apparatus being configured to capture an image of the cell using the line camera to acquire and output first imaging data; a second observation apparatus including an area camera and a second optical system , the second observation apparatus being configured to capture an image of the cell using the area camera to acquire second imaging data; and a control device configured to analyze the first imaging data output from the first observation apparatus to determine whether the cell satisfies a specific condition, to instruct the area camera to output the second imaging data of the cell determined to satisfy the specific condition, and to analyze the second imaging data output from the second observation apparatus to determine whether the cell is a specific cell; characterized in that the control device is configured to analyze the first imaging data to determine whether there is a cell suspected as a cancer cell, and to analyze the second imaging data to determine whether the cell is a cancer cell, and wherein the area camera comprises a built-in memory of a ring buffer type and is configured to sequentially store the second imaging data at each time point in said built-in memory of a ring buffer type, receive the output instruction from the control device , suspend storing of new second imaging data to the built-in memory when receiving the output instruction, output the second imaging data over a predetermined period of time in the past among the second imaging data stored in the built-in memory at that time, and restart storing of the second imaging data after ending the output of the second imaging data. <EOS>