AUTOMATIC ANALYZER

PROBLEM TO BE SOLVED: To efficiently utilize reagent cassettes set in a main reagent buffer and a sub-reagent buffer and to smoothly carry out analysis work without any interference.SOLUTION: In an automatic analyzer including a main reagent buffer 7a and a sub-reagent buffer 7b, a collection of reagent cassettes 6 (essential reagent cassette group) to be stored in the main reagent buffer 7a, the essential reagent cassette group, and a plurality of switching conditions thereof are set. It is checked whether the switching conditions of the essential reagent cassette group are satisfied. During switching, it is evaluated whether a reagent cassette 6 designated in the essential reagent cassette group has been stored in the main reagent buffer 7a or the sub-reagent buffer 7b. When it is present only in the sub-reagent buffer 7b, a reagent cassette transfer mechanism 7c is controlled to transfer the reagent cassette 6 to the main reagent buffer 7a. When it is present in neither the main reagent buffer 7a nor the sub-reagent buffer 7b, control is performed to display a name of the reagent cassette 6 and to prompt an input.