An automatic analyzer comprising: a reagent container which contains a reagent; reagent container placement mechanisms (28, 29) configured to place a plurality of the reagent containers; a reagent dispensing probe with a mechanism for transferring the position of a nozzle configured to aspirate a predetermined amount of a reagent held in the reagent containers on the reagent container placement mechanisms (28, 29), before discharging the aspirated reagent into a reaction container, and a reagent container transfer mechanism configured to transfer the reagent containers to the reagent container placement mechanisms (28, 29); wherein the reagent dispensing probe and the reagent container transfer mechanism are configured to interfere with one another by moving at the same height; the automatic analyzer further including: a position detection mechanism configured to detect the position of at least either the reagent dispensing probe or the reagent container transfer mechanism, characterized in that: the position detection mechanism is configured to divide a detection area into a plurality of regions so as to detect the region in which either the reagent dispensing probe or the reagent container transfer mechanism is present, such regions being either resettable or non-resettable regions, wherein a non-resettable region is a region where there is a risk of interference between the reagent container transfer mechanism and the reagent dispensing probe and a resettable region is a region where there is not risk of interference; and the automatic analyzer further comprises a control mechanism configured so that, if the position detection mechanism detects that the reagent dispensing probe is in the non-resettable region, the control mechanism performs control not to transfer the reagent container transfer mechanism by inhibiting a reset operation thereof, and if the position detection mechanism detects that the reagent container transfer mechanism is in the non-resettable region, the control mechanism performs control not to transfer the reagent dispensing probe by inhibiting a reset operation thereof. a reagent container which contains a reagent; reagent container placement mechanisms (28, 29) configured to place a plurality of the reagent containers; a reagent dispensing probe with a mechanism for transferring the position of a nozzle configured to aspirate a predetermined amount of a reagent held in the reagent containers on the reagent container placement mechanisms (28, 29), before discharging the aspirated reagent into a reaction container, and a reagent container transfer mechanism configured to transfer the reagent containers to the reagent container placement mechanisms (28, 29); wherein the reagent dispensing probe and the reagent container transfer mechanism are configured to interfere with one another by moving at the same height; the automatic analyzer further including: a position detection mechanism configured to detect the position of at least either the reagent dispensing probe or the reagent container transfer mechanism, characterized in that: the position detection mechanism is configured to divide a detection area into a plurality of regions so as to detect the region in which either the reagent dispensing probe or the reagent container transfer mechanism is present, such regions being either resettable or non-resettable regions, wherein a non-resettable region is a region where there is a risk of interference between the reagent container transfer mechanism and the reagent dispensing probe and a resettable region is a region where there is not risk of interference; and the automatic analyzer further comprises a control mechanism configured so that, if the position detection mechanism detects that the reagent dispensing probe is in the non-resettable region, the control mechanism performs control not to transfer the reagent container transfer mechanism by inhibiting a reset operation thereof, and if the position detection mechanism detects that the reagent container transfer mechanism is in the non-resettable region, the control mechanism performs control not to transfer the reagent dispensing probe by inhibiting a reset operation thereof. the position detection mechanism is configured to divide a detection area into a plurality of regions so as to detect the region in which either the reagent dispensing probe or the reagent container transfer mechanism is present, such regions being either resettable or non-resettable regions, wherein a non-resettable region is a region where there is a risk of interference between the reagent container transfer mechanism and the reagent dispensing probe and a resettable region is a region where there is not risk of interference; and the automatic analyzer further comprises a control mechanism configured so that, if the position detection mechanism detects that the reagent dispensing probe is in the non-resettable region, the control mechanism performs control not to transfer the reagent container transfer mechanism by inhibiting a reset operation thereof, and if the position detection mechanism detects that the reagent container transfer mechanism is in the non-resettable region, the control mechanism performs control not to transfer the reagent dispensing probe by inhibiting a reset operation thereof.