Abstract: An automatic analyzer includes a transportation line that executes carrying-in/out of a sample rack in which a sample is mounted from/to an analyzation unit, a cold storage that cools a plurality of the sample racks in which the sample having been measured in the analyzation unit is mounted, a transportation control unit that executes operation control for carrying-in of the sample rack from the transportation line to the cold storage and operation control for carrying-out of the sample rack from the cold storage to the transportation line, a front chamber that is disposed between the cold storage and the transportation line, the inner space of the front chamber being shielded from the outside, and a temperature/humidity control unit that controls temperature of the inside of the front chamber to temperature/humidity between those of the outside of the cold storage and those of the inside of the cold storage.