[Problem] To provide a foldable frame structure that expands into a 2N polygon (N being an integer of at least 2), maintains stability and has high rigidity when extended, and is compact when folded. [Solution] A frame structure comprising first coupling means (220) that are arranged so as to couple 2N upper rods (210) of equal length to form a flat 2N-sided polygon, each first coupling means (220) holding two upper rods (210) so as to couple adjacent upper rods (210) at each vertex of the 2N polygon and allow the upper rods (210) to freely rotate around an orthogonal axis (AX2), which is orthogonal to both of the center shafts (AX1) of the two upper rods (210), and rotating means (240) that allow each upper rod (210) to rotate around the center shaft (AX1), wherein the upper rods (210) can be rotated around the center shafts (AX1) while being pivoted around the orthogonal axes (AX2) such that the angle formed by two adjacent upper rods (210) is minimized, thus enabling the entire structure to be folded into
