A planar reflector is composed of a base (8) and a flexible substrate (5) having a high reflection layer (6) formed thereon and overlayed on the base (8) with an adhesive layer (7) interposed between the high reflection layer and the base. The adhesion strength between the base and the substrate is at least 100 g/cm, and the thickness of the adhesive layer is not smaller than 0.5 µm but not greater than 50 µm. A curved reflector can be obtained by bending the planar reflector so that a curved surface having a curvature of radius not greater than 5 mm is formed presenting a concave surface on a side of the flexible substrate.