A flexible battery and method for manufacturing a flexible battery in which an electrode assembly is encapsulated by an exterior material with an electrolyte. The flexible battery may be provided with an electrode assembly manufactured by forming a positive electrode mixture by coating and drying a composition for forming a positive electrode active material on part or all of at least one surface of a positive electrode current collector; vacuum drying the positive electrode current collector to manufacture a positive electrode; forming a negative electrode mixture by coating and drying a composition for forming a negative electrode active material on part or all of at least one surface of a negative electrode current collector; vacuum drying the negative electrode current collector to manufacture a negative electrode; and laminating by interposing a separator between the positive electrode and the negative electrode.