A flexible organic single crystal has a plurality of columns. The plurality of columns includes a plurality of planar organic compounds arranged so that molecular planes of molecules are respectively parallel to each other. As the organic compound, an organic compound is used that has a large molecular plane and a large area overlapping on an adjacent organic compound due to an intermolecular interaction. Further, energy changes in proportion to a strain. In this structure, when force along the direction of a stack axis is exerted, an angle formed by the stack axis and the normal of the molecular plane of the organic compound changes. Thus, the single crystal obtains flexibility.