The present invention has been made taking the abovementioned problem into consideration, and an object of the present invention is to provide an automatic analyzer, wherein the processing ability hardly decreases even when a plurality of analyses, each of which requires the different reaction time, exist in parallel. There is provided an analyzer comprising: 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 analyzer 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.