An automated analyzer, comprising: a reaction disk configured to circumferentially accommodate a plurality of reaction vessels; a sample dispensing mechanism configured to dispense a predetermined amount of a sample into the reaction vessel; a reagent dispensing mechanism configured to dispense a predetermined amount of a reagent into the reaction vessel; a stirring mechanism configured to stir the sample and the reagent dispensed into the reaction vessel; a measurement unit configured to measure a mixture of the sample and the reagent in the reaction vessel in a reaction process and/or a reaction solution after the reaction; a washing mechanism configured to clean the reaction vessel; and a controller, wherein in a period when cyclic measurement by the measurement unit is not necessary, the controller is configured to control the washing mechanism to perform cleaning of the reaction vessel in a washing cycle (503, 1003) having a cycle time shorter than that of an analysis cycle (501, 1001), the analysis cycle (501, 1001) and the washing cycle (503, 1003) each include a stopping period and a rotation period of the reaction disk in one cycle, in the analysis cycle (501, 1001), the controller is configured to control all of the sample dispensing mechanism, the reagent dispensing mechanism, the stirring mechanism, and the washing mechanism such that each have a time to operate in the stopping period, and the measurement unit is configured to perform a measurement in the rotation period, characterized in that: in the washing cycle (503, 1003), the controller is configured to control any one of the sample dispensing mechanism, the reagent dispensing mechanism, and the stirring mechanism such that they do not have a time to operate, and to control the washing mechanism such that it has a time to operate in the stopping period, and a stopping period of the washing cycle (503, 1003) is shorter than the stopping period of the analysis cycle (501, 1001), and a rotation amount of the reaction disk in the rotation period of the analysis cycle (501, 1001) is equal to a rotation amount of the reaction disk in the rotation period of the washing cycle. a reaction disk configured to circumferentially accommodate a plurality of reaction vessels; a sample dispensing mechanism configured to dispense a predetermined amount of a sample into the reaction vessel; a reagent dispensing mechanism configured to dispense a predetermined amount of a reagent into the reaction vessel; a stirring mechanism configured to stir the sample and the reagent dispensed into the reaction vessel; a measurement unit configured to measure a mixture of the sample and the reagent in the reaction vessel in a reaction process and/or a reaction solution after the reaction; a washing mechanism configured to clean the reaction vessel; and a controller, wherein in a period when cyclic measurement by the measurement unit is not necessary, the controller is configured to control the washing mechanism to perform cleaning of the reaction vessel in a washing cycle (503, 1003) having a cycle time shorter than that of an analysis cycle (501, 1001), the analysis cycle (501, 1001) and the washing cycle (503, 1003) each include a stopping period and a rotation period of the reaction disk in one cycle, in the analysis cycle (501, 1001), the controller is configured to control all of the sample dispensing mechanism, the reagent dispensing mechanism, the stirring mechanism, and the washing mechanism such that each have a time to operate in the stopping period, and the measurement unit is configured to perform a measurement in the rotation period, characterized in that: in the washing cycle (503, 1003), the controller is configured to control any one of the sample dispensing mechanism, the reagent dispensing mechanism, and the stirring mechanism such that they do not have a time to operate, and to control the washing mechanism such that it has a time to operate in the stopping period, and a stopping period of the washing cycle (503, 1003) is shorter than the stopping period of the analysis cycle (501, 1001), and a rotation amount of the reaction disk in the rotation period of the analysis cycle (501, 1001) is equal to a rotation amount of the reaction disk in the rotation period of the washing cycle. in the washing cycle (503, 1003), the controller is configured to control any one of the sample dispensing mechanism, the reagent dispensing mechanism, and the stirring mechanism such that they do not have a time to operate, and to control the washing mechanism such that it has a time to operate in the stopping period, and a stopping period of the washing cycle (503, 1003) is shorter than the stopping period of the analysis cycle (501, 1001), and a rotation amount of the reaction disk in the rotation period of the analysis cycle (501, 1001) is equal to a rotation amount of the reaction disk in the rotation period of the washing cycle.