An automatic analyzing device comprising a holder for movably holding a plurality of reagent containers ; a reagent refrigerator for covering a periphery of the holder; a reagent loader adapted to pass through an opening disposed in part of the reagent refrigerator to carry in/out each reagent container with respect to the holder; an instruction unit for instructing movement of the reagent loader; a storage unit for storing device states including a standby state and an analyzing state, a first reagent carry-in/out mode related to the reagent loader according to the standby state, and a second reagent carry-in/out mode related to the reagent loader according to the analyzing state; and a control unit for detecting an instruction from the instruction unit means and controlling operations of the holder and the reagent loader so as to execute the first reagent carry-in/out mode, when the device state is the standby state, and the second reagent carry in/out mode, when the device state is the analyzing state, wherein the standby state is a state in which analysis of a sample can be started in response to an analysis instruction of the sample, and the analysis of the sample has not been started, and the analyzing state is a state in which the analysis of the sample has been started, characterized in that - the first reagent carry-in/out mode is a mode configured to sequentially continue the reagent carry-in of the reagent loader until no reagent container is left on the reagent loader to be carried in and wherein the carried-in reagent containers are sequentially subjected to a reagent preparing operation after having completed the reagent container carry-in/out processing, and - the second reagent carry-in/out mode is a mode configured to discontinue reagent carry-in/out of reagent containers on the reagent loader upon having carried in one reagent container. a holder for movably holding a plurality of reagent containers ; a reagent refrigerator for covering a periphery of the holder; a reagent loader adapted to pass through an opening disposed in part of the reagent refrigerator to carry in/out each reagent container with respect to the holder; an instruction unit for instructing movement of the reagent loader; a storage unit for storing device states including a standby state and an analyzing state, a first reagent carry-in/out mode related to the reagent loader according to the standby state, and a second reagent carry-in/out mode related to the reagent loader according to the analyzing state; and a control unit for detecting an instruction from the instruction unit means and controlling operations of the holder and the reagent loader so as to execute the first reagent carry-in/out mode, when the device state is the standby state, and the second reagent carry in/out mode, when the device state is the analyzing state, wherein the standby state is a state in which analysis of a sample can be started in response to an analysis instruction of the sample, and the analysis of the sample has not been started, and the analyzing state is a state in which the analysis of the sample has been started, - the first reagent carry-in/out mode is a mode configured to sequentially continue the reagent carry-in of the reagent loader until no reagent container is left on the reagent loader to be carried in and wherein the carried-in reagent containers are sequentially subjected to a reagent preparing operation after having completed the reagent container carry-in/out processing, and - the second reagent carry-in/out mode is a mode configured to discontinue reagent carry-in/out of reagent containers on the reagent loader upon having carried in one reagent container. <EOS>