Abstract: The present invention provides a sample measuring device capable of allowing not only one but more than one kind of samples to react with a reagent, and enhancing a reliability in photometric analysis accuracy by reliably mixing and agitating the sample and the reagent prior to the photometric analysis. The device includes a reagent melting/mixing means, a sample supply chamber positioned on the upstream side of, and communicating with, the reagent melting/mixing means when the sample is allowed to flow into the reagent melting/mixing means, and at least one measuring chamber positioned on the downstream side of, and communicating with, the reagent melting/mixing means, wherein the sample supply chamber, the reagent melting/mixing means, and the measuring chamber are arranged sequentially from the upstream to the downstream directions of the flow passage, with the sample supply chamber positioned on the upstream side with respect to the sample flow by a sample moving means.