and the washing reagent bottle 154 the reagent dispensing nozzle washing tank 121 and the flow path which connects the washing reagent supply hole 122 and the washing reagent bottle 154 with the detection reaction auxiliary reagent or the washing reagent during the system reagent replacement the system reagents namely the detection reaction auxiliary reagent and the washing reagent are charged into the system reagent supply nozzles and the system reagent reservoirs from the system reagent bottles and thus preparation for the detection step is carried out also the washing reagent is supplied to the reagent dispensing nozzle washing tank from the washing reagent bottle and thus preparation for the reagent dispensing step is carried out the system reagent replacement is characterized in that the time required is the longest among the operation items of the analysis preparation operation because the solutions remaining in the system reagent supply nozzles the system reagent reservoirs and the reagent probe washing tank are replaced with the system reagents which are supplied from the system reagent bottles of the detection reaction auxiliary reagent and the washing reagent and because the system reagents have to be supplied more than once in amounts corresponding to the total volumes of the flow paths and the reservoirs and the washing reagent supply hole of the reagent probe washing tank the disposal of the reaction containers is an operation item for disposing of the reaction containers 105 which remain on the incubator disk 104 and in the stirring mechanism 108 during the disposal of the reaction containers it is checked whether there are reaction containers 105 remaining on the incubator disk 104 and in the stirring mechanism 108 and the disposal operation is carried out the disposal of the reaction containers is characterized.