Cell culture apparatus and method of culturing cells

A cell culture apparatus comprising:

• a culture tank that can contain a culture medium and cells in its interior;
• a culture-medium supply path to supply the culture medium to the culture tank;
• and
• a culture-medium discharge path to discharge the culture medium from the culture tank,
• wherein the culture tank comprises:
• a division wall that selectively divides an internal space of the culture tank in a direction of gravity into an upper space and a lower space,
• an inlet through which the culture-medium supply path supplies the culture medium to the interior, and
• an outlet through which the culture-medium discharge path discharges the culture medium from the interior,
• wherein the outlet opens into the upper space, and
• wherein the division wall includes a plurality of plate members, and changing relative positions of the plurality of plate members enables switching between a state where the internal space of the culture tank is divided into the upper space and the lower space and a state where the upper space and the lower space are in communication with each other.