A film manufacturing apparatus includes a lamination unit that laminates a first layer at one side in a thickness direction of a long-length substrate film to produce a one-sided laminated film, and that laminates a second layer at the other side in the thickness direction of the one-sided laminated film to produce a double-sided laminated film; a conveyance unit; a marking unit; a measurement unit; a detection unit, disposed at an upstream side in the conveyance direction of the measurement unit; and an arithmetic unit that obtains physical properties of the first layer and the second layer based on the physical property at a first position in the one-sided laminated film and the physical property at a second position in the double-sided laminated film. The arithmetic unit defines, with a mark as a reference, a position substantially the same as the first position to be the second position.