The automatic analyzer includes: a disk having a plurality of holding sections for holding a plurality of containers on the circumference of the disk or on a closed loop that rotationally moves, the disk adapted to move the plurality of containers; a reagent dispensing mechanism for dispensing a reagent into the container on the disk; and a sample dispensing mechanism for dispensing a sample into the container on the disk. The automatic analyzer also includes a container transfer mechanism for mounting the container in the holding sections on the disk. The container transfer mechanism is driven in such a manner that the container can be mounted in the plurality of holding sections on the disk.