An automatic analysis device and method having a BF separation process, wherein the width in a container conveyance direction of a surface facing a reaction container of a magnet for preliminary magnetic collection of a first magnetic generation part (32p) is set to have a length including a region for housing a liquid sample of the reaction container conveyed to a magnetic collection position of the first magnetic generation part. An end in the container conveyance direction of a surface facing the reaction container of a magnet for regular magnetic collection of a second magnetic generation part (32m) is designed to be close to the center of the region for housing the liquid sample of the reaction container conveyed to a magnetic collection position of the second magnetic generation part.