A conventional automated analyzer has a mechanism for performing a stirring operation and a mechanism for performing a pipetting operation. The mechanisms are independent of each other. The time interval between the stirring operation and the pipetting operation is at least several seconds. A solid particle starts to settle out at the time of termination of the stirring operation. In the pipetting operation, an operation for suctioning a liquid is performed during a transient period of the process in which the solid particle settles out. The suction of the liquid containing a solid particle during the transition period of the process may cause a variation in the number of solid particles contained in the liquid pipetted. The problem is solved by means for simultaneously performing an operation for stirring a liquid reagent containing a solid particle and an operation for maintaining the reagent.
