An automatic analyzer comprising: an analyzing unit (48, 49) that is adapted to analyze a sample; and a temperature adjusting unit that is adapted to adjust a temperature of a reagent required to analyze the sample in advance and supply the reagent to the analyzing unit (48, 49), wherein the temperature adjusting unit includes: a first reagent storage portion that is adapted to store a reagent in a spiral-shaped pipe having a first reagent storage volume; a second reagent storage portion that has a second reagent storage volume, is connected to the first reagent storage portion and is supplied with a reagent from the first reagent storage portion, characterized in that the temperature adjusting unit further includes: a metal block connected to a Peltier element, wherein a heat diffusion plate is connected to the metal block via a first thermal interface, and the Peltier element is connected to the metal block via a second thermal interface, the Peltier element is adapted to adjust temperatures of the first reagent storage portion and the second reagent storage portion, and the second reagent storage portion is a pipe which is thicker and shorter than the first reagent storage portion so that its volume per length is larger. an analyzing unit (48, 49) that is adapted to analyze a sample; and a temperature adjusting unit that is adapted to adjust a temperature of a reagent required to analyze the sample in advance and supply the reagent to the analyzing unit (48, 49), wherein the temperature adjusting unit includes: a first reagent storage portion that is adapted to store a reagent in a spiral-shaped pipe having a first reagent storage volume; a second reagent storage portion that has a second reagent storage volume, is connected to the first reagent storage portion and is supplied with a reagent from the first reagent storage portion, characterized in that the temperature adjusting unit further includes: a metal block connected to a Peltier element, wherein a heat diffusion plate is connected to the metal block via a first thermal interface, and the Peltier element is connected to the metal block via a second thermal interface, the Peltier element is adapted to adjust temperatures of the first reagent storage portion and the second reagent storage portion, and the second reagent storage portion is a pipe which is thicker and shorter than the first reagent storage portion so that its volume per length is larger. a first reagent storage portion that is adapted to store a reagent in a spiral-shaped pipe having a first reagent storage volume; a second reagent storage portion that has a second reagent storage volume, is connected to the first reagent storage portion and is supplied with a reagent from the first reagent storage portion, characterized in that the temperature adjusting unit further includes: a metal block connected to a Peltier element, wherein a heat diffusion plate is connected to the metal block via a first thermal interface, and the Peltier element is connected to the metal block via a second thermal interface, the Peltier element is adapted to adjust temperatures of the first reagent storage portion and the second reagent storage portion, and the second reagent storage portion is a pipe which is thicker and shorter than the first reagent storage portion so that its volume per length is larger.