A temperature-controlled bath capable of swiftly changing the temperature of a sample to a target temperature and maintaining the temperature of the sample at a fixed temperature after the temperature change is provided. A temperature-controlled bath includes a temperature changing means, a temperature-controlled chamber, a sample holding chamber, and connection cut-off means. The temperature changing means is disposed in the temperature-controlled chamber, and the temperature of the temperature-controlled chamber is adjusted by the temperature changing means. The sample holding chamber is separated from the temperature-controlled chamber by a thermally conducive wall, and contains a sample therein. The connection cut-off means change a connection between the temperature-controlled chamber and the sample holding chamber to a connected state or a cut-off state.