An automatic analyzer comprising: reagent amount detecting means for detecting the remaining amounts of a plurality of reagents; an analysis device (5, 6, 7) for performing analysis operation including sampling specimens and analysing the specimen samples using a reagent of the plurality of reagents; and control means for controlling the analysis device, characterized in that when said reagent amount detecting means have detected that the remaining amount of a reagent used for an ongoing analysis has fallen to a predetermined threshold value or less, the control means are adapted to control the analysis device to stop specimen sampling, to complete analysing the current specimen sample and then to assume a standby state without performing a post-analysis operation such as cleaning a probe or discarding a reaction cup; and when the reagent amount detecting means have detected that the remaining amount of the reagent used for said ongoing analysis has been replenished, the control means are adapted to control the analysis device to change from the standby state to an operation state and to resume analysis operation without performing a pre-analysis operation such as cleaning a probe or discarding a reaction cup. reagent amount detecting means for detecting the remaining amounts of a plurality of reagents; an analysis device (5, 6, 7) for performing analysis operation including sampling specimens and analysing the specimen samples using a reagent of the plurality of reagents; and control means for controlling the analysis device, characterized in that when said reagent amount detecting means have detected that the remaining amount of a reagent used for an ongoing analysis has fallen to a predetermined threshold value or less, the control means are adapted to control the analysis device to stop specimen sampling, to complete analysing the current specimen sample and then to assume a standby state without performing a post-analysis operation such as cleaning a probe or discarding a reaction cup; and when the reagent amount detecting means have detected that the remaining amount of the reagent used for said ongoing analysis has been replenished, the control means are adapted to control the analysis device to change from the standby state to an operation state and to resume analysis operation without performing a pre-analysis operation such as cleaning a probe or discarding a reaction cup. when said reagent amount detecting means have detected that the remaining amount of a reagent used for an ongoing analysis has fallen to a predetermined threshold value or less, the control means are adapted to control the analysis device to stop specimen sampling, to complete analysing the current specimen sample and then to assume a standby state without performing a post-analysis operation such as cleaning a probe or discarding a reaction cup; and when the reagent amount detecting means have detected that the remaining amount of the reagent used for said ongoing analysis has been replenished, the control means are adapted to control the analysis device to change from the standby state to an operation state and to resume analysis operation without performing a pre-analysis operation such as cleaning a probe or discarding a reaction cup.