Disclosed is a container that is capable of maintaining articles requiring thermal management at a prescribed temperature over long periods of time without being influenced by the outside air temperature, and that is capable of storing and transporting the articles. The constant-temperature storage container is characterized by being equipped with a heat-insulating box, and two or more types of cold-storing materials or heat-storing materials disposed therein; by having a latent-heat first cold-storing material or heat-storing material (a) disposed in a solid state adjacent to an article being kept cool or warm, and a latent-heat second cold-storing material or heat-storing material (b) disposed in a molten state on the exterior of the aforementioned first cold-storing material or heat-storing material (a); and in that the solidifying and melting temperature of the aforementioned first cold-storing material or heat-storing material (a) exceeds 0 DEG C. The constant-temperature storage container is capable of maintaining the article being kept cool or warm in an arbitrary temperature range exceeding 0 DEG C for long periods of time.