Abstract: An aspect of the present invention makes it possible to easily observe both surfaces of a cell sheet in a condition in which the cell sheet is at a stable position in a culture medium. A cell sheet production device (100) includes: a container (20); and a support unit (10) removably held in the container (20), the support unit (10) including a mesh sheet (2) and a base (3) which holds the mesh sheet (2) such that the mesh sheet (2) floats from a bottom surface of the container (20), the support unit (10) being held in the container (20) such that the support unit is at a fixed position in vertical and horizontal directions in a culture medium.