The present invention reduces the turnaround time of an automated analyzer. During a period when cyclic measurement by a measurement unit is unnecessary, a controller washes a reaction vessel using a washing cycle having a cycle time shorter than that of an analysis cycle. A single analysis cycle and a single washing cycle both include a reaction disc stopping period and rotation period. In the washing cycle, there is no time during the stopping period when a sample dispensing mechanism, reagent dispensing mechanism, or stirring mechanism operates but there is a time when a washing mechanism operates. The washing cycle stopping period is shorter than the analysis cycle stopping period. The amount of rotation of the reaction disk in the analysis cycle rotation period is the same as the amount of rotation of the reaction disk in the washing cycle rotation period.