Automatic analyzer

An automatic analyzer comprising:

• a specimen container conveying unit which conveys a specimen container along a first track;
• a reaction unit which promotes a reaction of a specimen in a reaction container installed in the reaction unit;
• a specimen dispensing unit which extends vertically, moves along a second track that intersects the first track, sucks a specimen from a specimen container positioned at a predetermined specimen suction position and has a nozzle that discharges the specimen into the reaction container installed in the reaction unit;
• a measuring unit which measures a reaction solution in the reaction container, and
• a single housing in which all of the units are mounted, wherein
• the housing includes a first alignment portion that, in concert with a second alignment portion on the specimen container conveying unit, aligns the specimen container conveying unit with the housing, the specimen container conveying unit is configured to be exchangeable with a plurality of other specimen container conveying units that are different from each other and the specimen container conveying unit in at least one of structure and components, each of the plurality of other specimen container conveying units having a respective corresponding first track, and a respective corresponding second alignment portion identical to the second alignment portion on the specimen container conveying unit, and has a shape common to the plurality of other specimen container conveying units, and
• alignment is performed by the first alignment portion aligning with either the second alignment portion of the specimen container conveying unit or the second alignment portion of one of the other specimen container conveying units such that the second track intersects with either the first track of the specimen container conveying unit or the first track of one of the other specimen container conveying units at a same position regardless of which of the plurality of other specimen container conveying units is exchanged for the specimen container conveying unit.