There are disclosed a releasing sheet comprising a substrate and a releasing agent layer which is installed by coating the substrate with a releasing agent liquid containing 1,4-polybutadiene and an antioxidant, and irradiating the coated layer with ultraviolet ray so that the layer is cured; and also a releasing sheet comprising in turn a substrate, an undercoat layer which is formed thereon and is composed of an elastic body, and a releasing agent layer which is installed on the undercoat layer by coating the same with a releasing agent liquid containing 1,4-polybutadiene and an antioxidant, and irradiating the layers with ultraviolet ray so that the layers are cured. Being of non-silicone base, the releasing sheets are excellent in releasability from a tacky adhesive agent layer and adhesiveness to the substrate.